Pushback against DDOS Attacks

Huusker writes "Steven Bellovin and others at ATT Research Labs and ICIR have come up with mechanism to stop DDOS attacks. The idea is called Pushback. When the routers get flooded they consult a Unix daemon (/etc/pushbackd) to determine if they are being DDOS'ed. The routers propagate the quench packets back to the sources. The policy and propagation are separate, allowing hardware vendors to concentrate on the quench protocol while the white hats invent ever more clever DDOS detection filters for /etc/pushbackd. The authors of the paper have an initial implementation on FreeBSD."

Comments

dood

[exspecto]

im so 1337.

fp biatches

hey

[Anonymous Coward]

even better idea!

shut off the computer if its getting DoS'd

(FP?)

Re:hey

[autocracy]

That's exactly what this would do. The DDOS'd routers tell their upstream routers to cut back the flow of traffic - basically cutting out the source of the traffic. This of course requires that the upstream routers agree to do this...

Re:hey

[autocracy]

I'd like to withdraw/modify that statement. I read the top post too fast :)

It would shut off the source of the flood, not the destination as the original poster implied...

Re:hey

[thefalconer]

Why do that? That's exactly what the stupid script kiddies who are dos'ing you want! They're trying to forcefully shut down your server, so if you do it yourself, they won. The idea is to block them out, return fire and remain online. That's how you win against them.

Re:hey

[Anonymous Coward]

yea um, i posted that as a joke, not a serious statement. if i scripted protection, i would make it nuke them back!

Re:hey

[Anonymous Coward]

I just had a crazy idea. Lets say some enterprising script kiddie wants to shut off the internet. All he would need to do, after this daemon was implemented, is unleash his latest VB virus that spoofs a range of IP's. One day these infected computers would communicate among themselves to determine which blocks to spoof. Then, like the Michaelangelo virus, strike on the same day, spoofing every IP in existence and some that aren't in a dos attack from a couple million computers. After all the IP's are spoffed, those that have been attacked retaliate, only making the DOS worse. By the time it is all done, every router has blocked every IP in existence, effectively shutting off the internet. One big off switch, that is what this is. :-)

This sounds like the Tim Allen sort of way to do it. "Why don't we just throw it against the wall and save you the trouble?"

Food for thought.

*BSD can drink my *pee

[Anonymous Coward]

Problem?

[prichardson]

Unfortunately the DDOS'ers will simply find a new way to flood a system. The best way to defend against this is to have a backup plan for when your servers get hosed.

Re:Problem?

[thefalconer]

Yes, but this would also stop most typical script kiddies. Those are the most malicious ones. Lack of maturity combined with lots of "god complex" tend to cause them to do far more damage than a typical hacker/ddos'er. So if you shut them down or reverse dos them, then they get a taste of their own medicine and you get to laugh while they're trying to figure out why their system just took a dive. :)

Re:Problem?

[prichardson]

Ah yes, but i was thinking far enough into the futire when this uninvented new attack is just as commonplace as the DDoS is now. I'm sure the DDoS was a truly godlike acompleshment in its day

Re:Problem?

[Sn4xx0r]

So if you shut them down or reverse dos them, then they get a taste of their own medicine and you get to laugh while they're trying to figure out why their system just took a dive. :)

I don't think you get it (or I misread the article). The first D in DDoS stands for distributed. In a distributed denial of service attack many, many clients all attack a target at once. You can assume that the machine of the guy that directs the attack is not among the attacking machines.

A reverse DoS would only annoy some people that probably don't even know that their machine is being used in an attack. A better response (if it were possible) would be to send them instructions on securing their machines.

Re:Problem?

[sfe_software]

I agree that this doesn't, on the surface, seem to be a good idea. My question is this: don't some DDoS attacks spoof the source IP anyway? I believe that this is easily done, as long as you don't care about getting a return value. Being attacked in this manner would cause the victim to "push back" against another unsuspecting victim...

Or am I missing something (or just wrong)?

Re:Problem?

[Sn4xx0r]

The way I see it is that idea is to throttle the datastream going to the attacked IP, at all the routers up to the originating IP(s), not to bounce the packets back to the originating IP(s). It's the only thing that would make sense. If so, the choice of words in the writeup is a bit confusing. But then again, I'm easily confused :)

Re:Problem?

[Anonymous Coward]

The above poster is 100% correct. Defining and throttling 'evil' traffic is the best way to go. Most router vendors have some methos of identifying traffic profiles and implementing a L2-cognicent policy.

Here is a Cisco IOS policy that will identify and throttle all ICMP echo traffic that consumes greater than 256K.

policy class-map match-all DOS
match access-group 189

policy-map killicmp
class DOS
police 256000 8000 8000 conform-action transmit exceed-action drop

access-list 189 permit icmp any any echo
access-list 189 permit icmp any any echo-reply

Couldnt pushback be a Dos tool in itslf?

[Anonymous Coward]

If pushback is subverted, couldnt it function like an inverse DOD tool?

Re:Couldnt pushback be a Dos tool in itslf?

[keller]

Department of Defense should use this?
Why? .K

Re:Couldnt pushback be a Dos tool in itslf?

[Masami Eiri]

I think he meant DDoS, not DoD

Re:Couldnt pushback be a Dos tool in itslf?

[Anonymous Coward]

No because it means stop sending. To the network this stops the flood of packets.

and as the flood stop makes it,s way up the network to the source more and more bandwith is avalibale to the network untill hopefully even the ofending machines will ack and stop sending.

But even if the ofending machine wont the routers
in between the target and the source will.

CCNA

Re:Couldnt pushback be a Dos tool in itslf?

[xenocide2]

What he means is that pushback is a form of muting a computer. Pushback just sends the filters upstream to stop the saturation of the line. If this mechanism is vulnerable in some form that is universal or at least common then you could subjugate the filtering mechanism to mute a target upstream. Don't like GRC? Hack a pushback capable router and tell it to drop all send packets from GRC.

Re:Couldnt pushback be a Dos tool in itslf?

[swillden]

No because it means stop sending. To the network this stops the flood of packets.

Yes but if the system can be fooled into quenching legitimate requests then service has still been denied. I mean, to a user, does it matter if you can't get to the server because it's overloaded, or you can't get to the server because the routers are telling your machine to stop sending? Either way, all you know is that the blasted server is down.

*BSD is dying

[Anonymous Coward]

It is official; Netcraft now confirms: *BSD is dying

One more crippling bombshell hit the already beleaguered *BSD community when IDC confirmed that *BSD market share has dropped yet again, now down to less than a fraction of 1 percent of all servers. Coming on the heels of a recent Netcraft survey which plainly states that *BSD has lost more market share, this news serves to reinforce what we've known all along. *BSD is collapsing in complete disarray, as fittingly exemplified by failing dead last in the recent Sys Admin comprehensive networking test.

You don't need to be a Kreskin to predict *BSD's future. The hand writing is on the wall: *BSD faces a bleak future. In fact there won't be any future at all for *BSD because *BSD is dying. Things are looking very bad for *BSD. As many of us are already aware, *BSD continues to lose market share. Red ink flows like a river of blood.

FreeBSD is the most endangered of them all, having lost 93% of its core developers. The sudden and unpleasant departures of long time FreeBSD developers Jordan Hubbard and Mike Smith only serve to underscore the point more clearly. There can no longer be any doubt: FreeBSD is dying.

Let's keep to the facts and look at the numbers.

OpenBSD leader Theo states that there are 7000 users of OpenBSD. How many users of NetBSD are there? Let's see. The number of OpenBSD versus NetBSD posts on Usenet is roughly in ratio of 5 to 1. Therefore there are about 7000/5 = 1400 NetBSD users. BSD/OS posts on Usenet are about half of the volume of NetBSD posts. Therefore there are about 700 users of BSD/OS. A recent article put FreeBSD at about 80 percent of the *BSD market. Therefore there are (7000+1400+700)*4 = 36400 FreeBSD users. This is consistent with the number of FreeBSD Usenet posts.

Due to the troubles of Walnut Creek, abysmal sales and so on, FreeBSD went out of business and was taken over by BSDI who sell another troubled OS. Now BSDI is also dead, its corpse turned over to yet another charnel house.

All major surveys show that *BSD has steadily declined in market share. *BSD is very sick and its long term survival prospects are very dim. If *BSD is to survive at all it will be among OS dilettante dabblers. *BSD continues to decay. Nothing short of a miracle could save it at this point in time. For all practical purposes, *BSD is dead.

Fact: *BSD is dying

Re:*BSD is dying

[Anonymous Coward]

You could at least vary the numbers in this, so as to make it APPEAR to be a valid report, different from the one you swiped it from (which also was bullshit)

Re:*BSD is dying

[exspecto]

hey, i havent seen the "stephen king dies" post in a while. someone post it please. i love recurring posts like this one, they remind me that people have a sense of humor.

Re:*BSD is dying

[Hektor_Troy]

Due to the troubles of Walnut Creek, abysmal sales and so on, FreeBSD went out of business and was taken over by BSDI who sell another troubled OS. Now BSDI is also dead, its corpse turned over to yet another charnel house.

Here's to hoping Microsoft picks up FreeBSD then.

Re:*BSD is dying

[Anonymous Coward]

Hmmmm, perhaps it's that the BSDs don't have hoards of people repackaging essentially the same thing and trying to turn it into a cash cow?
Get into the community before talking out of your ass. The IRC channels are strong, the usenet groups are strong, the mailing lists are strong, and yes, the changelog is still pumping.
All of your cute (and blatantly riped off) "statistics" are bullshit. And do you actually think that even a majority of the users are regulars on the groups? *BSD isn't dieing any more then Windows or Linux is. Get a life.

Dealing with the loss of FreeBSD

[Anonymous Coward]

Hey, although you might not be comfortable with the thought, most people agree that FreeBSD is dying. That is an honest assessment. You really can't argue with the truth, no matter how much the truth might hurt. Truth exists independent of your personal feelings. So suck it up, put your chin up and move on. The death of FreeBSD is not the end of the world. It certainly doesn't have to be the end of your world.

Manual RegEx?

[stevejsmith]

If a large-enough site was getting DDoS'd (Yahoo!, Microsoft, universities, etc.), wouldn't there be someone on call 24/7 who could in a matter of minutes sort out what the similarities in the DDoS are and then manually get a RegEx to sort them all out?

I don't have much knowledge of the subject, but that seems like an easy want to deal with it.

Re:Manual RegEx?

[mocktor]

Nice idea but regex's have waaaay to high an overhead to filter the amount of traffic even a small DDoS produces - you'd need some kind of omnipotent distributed uberBeowulf cluster (or a million monkeys watching a zillion blinkenlights)

Re:Manual RegEx?

[Bill Wong]

DDoS is usually bandwitdh consumption...
Even if you drop 100% of the evil packets...
Your pipe is still filled...

And for the amount of traffic needed to actually DDoS a large-enough site like Yahoo (4 gbps last time around?), RegExs wouldn't be helpful
since, the sheer amount of cpu required to process *every*single*packet*that*passes*through* is wayy too much...

Re:Manual RegEx?

[Mark (ph'x)]

yes, however if you do propagate the quench packets back towards the source, the idea is that its no longer your pipe that's being filled. this technique seems pretty good actually... imagining a large number of skript kidz filling up my pipe (dodgy image there ;) but I digress)... by 'quenching' each one of these at their ISP's router it means my pipe is empty, theirs is full and all they have succeded in doing is DOSing themselves :D

Re:Manual RegEx?

[Corfiot]

If you propagate upstream your pipe will *no*longer*be*filled*.

Plus, you don't process every single packet. Only dropped ones and of those, only a sample. Did you actually READ the paper?

Re:Manual RegEx?

[Anonymous Coward]

Did you read the post he was responding to?

God Bless AT&T Research!

[Anonymous Coward]

SYSTEM V ON YOUR ASS FOO'!

Hard Times for *BSD

[Anonymous Coward]

So why now? Why did *BSD fail? Once you get past the fact that *BSD is fragmented between a myriad of incompatible kernels, there is the historical record of failure and of failed operating systems. *BSD experienced moderate success about 15 years ago in academic circles. Since then it has been in steady decline. We all know *BSD keeps losing market share but why? Is it the problematic personalities of many of the key players? Or is it larger than their troubled personalities?

The record is clear on one thing: no operating system has ever come back from the grave. Efforts to resuscitate *BSD are one step away from spiritualists wishing to communicate with the dead. As the situation grows more desperate for the adherents of this doomed OS, the sorrow takes hold. An unremitting gloom hangs like a death shroud over a once hopeful *BSD community. The hope is gone; a mournful nostalgia has settled in. Now is the end time for *BSD.

Re:Hard Times for *BSD

[Luke-Jr]

"no operating system has ever come back from the grave"
I wasn't aware of that, but that's a good thing to hear. That means Windoze won't come back from the grave either. It died nearly a year ago. :)

sure

[bicho]

the best defense is the attack, so if they saturate your A/B/C network, then saturating the Internet is the obvious right solution.

Of course its not, it would do much more harm to many more innocent people.

The right solution is to educate people so that their PC's doesnt get inffected with worms and the like so they dont unknowingly contribute to DDOS.

Of course, the right is almost always the hard way and most people doesnt want to care about ignorant people so... we're in a vicious cycle here, just as in anything else.

Re:sure

[garcia]

educate people who are getting infected? Come on. Your not serious...

These people think that when they install virus scan software they are safe. I recently re-installed Windows on my gf's computer. She had V-Shield on there from 1999. She had no idea that she would need to update it.

At least my roommate, my parents, and my gf know (from me) not to open attachments. But educate a WIDE group of people? That's just not going to happen and you know it.

Re:sure

[jonbrewer]

She had V-Shield on there from 1999. She had no idea that she would need to update it.

Newer products do solve this problem without customer education. My McAfee VirusScan checks for updates daily and generally downloads new definitions once or twice a week. I don't have to take the initiative to update it or buy new software.

Re:sure

[Anonymous Coward]

that has to be one of the least constructive, head in the sand arguments I've ever read. Did you read the article ?

The technique is about making the internet move the point of dropping the flood packets, BACK closer to the source. That is, remove the flood from the internet itself, and contain it into the localised areas.

Instead of expecting the impossible as you suggest, (which is joe-average running a secure system), finally someone is thinking about securing the internet in general from unsecured systems, which is a pragmatic approach which may well protect the internet in general from many unforeseen DDOS attacks, as well as the ones we know about.

Re:sure

[Shishak]

Not exactly...

If every network provider ran this type of a system on their edge routers. Have all the edge routers communicate to distributed servers. Then, when you are being attacked you simply announce the offending IPs involved in the attack. That announcement gets propogated around all the servers which tell the edge devices to filter the traffic. It isn't a reverse flood. It is a way of telling the router closest to the source to start dropping packets.

Forged source IP's should be dropped at the edge already.

What we need is a protocol for sending dynamic filters to cisco routers. I would like to have input/output lists put on an interface that I can later build dynamically. I do it now with my Linux firewalls but it would be nice if I could drop the packets on the far side of my expensive link.

Re:sure

[Doug Neal]

How is this design proposing to saturate the Internet?

It involves sending a short message back to the routers that are routing the packets to you asking them to "quench" - i.e. filter out and don't route - the offending upstream sources.

The message could propagate as far back as the individual ISPs from which the packets are originating from so that each participant in the attack is cut off.

At least that's what I'm getting from the summary of the story, I could be completely wrong.

Re:sure

[irc.goatse.cx troll]

Not all denial of service is saturation.
What happens when i spoof that you just DoSed your favorite website? You get cut off from it, and denied service.

Although as far as taking advantage of this sort of thing goes, I'd much rather be able to use an ICMP Redirect to make a DoSnet packet its owner.

Re:sure

[Anonymous Coward]

So what kind of authentication is taking place between routers and the pushback daemon? Why couldn't I just create a denial of service by claiming that someone is denying me, therefore causing them to get shut down?

Re:sure

[Rhinobird]

how come your grandfather(gf) is a girl?

Re:sure

[LinuxGeek8]

If the router of your ISP would drop every packet that doesn't come from your ipadress, I should be safe.

Re:sure

[Anonymous Coward]

I don't have to take the initiative to update it or buy new software

Had it less than six months, huh?

Re:sure

[irc.goatse.cx troll]

Yes, because no one is so unethical that they would specify your ip address as the source instead of theirs.

The only thing to slow this down is checking routes, but even that can be gotten around (they just have to be on your network, thats not hard for colo's, shells, and most other providers)

Re:sure

[Anonymous Coward]

That's all well and good until your internet connection gets temporarily shut off just because you actually read the articles on /.

Re:sure

[pediddle]

A couple other people have said this already, but if I announce an "attack", who says that the attack is really taking place? Why can't I just tell the routers to quench some random "source" and cause a reverse DOS (wouldn't even need to be distributed)?

Re:sure

[Phroggy]

Forged source IP's should be dropped at the edge already.

Amazing how many ISPs don't do this...

Re:sure

[rbgrn]

> Forged source IP's should be dropped at the edge already.

No, They shouldn't! Forged sources are a way of getting 2 firewalled clients to talk directly to each other by means of spoofing each others filewalls with the forged source which is of the gatekeeper. It's the ONLY WAY to do this, and if you get rid of forged sources, you get rid of direct connections between firewalled IPs.

"from the build-a-better-asshole-trap dept."

[Anonymous Coward]

Here's a better asshole trap.

Not on linux yet?

[Anonymous Coward]

They didn't implement with linux because linux is the operating system for stupid wannabes.

100

[Anonymous Coward]

Who gives a fat fuck? *BSD is dying (Score:-1, Troll)
by Anonymous Coward on Tuesday October 22, @02:56PM (#4506374)
It is official; Netcraft now confirms: *BSD is dying

One more crippling bombshell hit the already beleaguered *BSD community when IDC confirmed that *BSD market share has dropped yet again, now down to less than a fraction of 1 percent of all servers. Coming on the heels of a recent Netcraft survey which plainly states that *BSD has lost more market share, this news serves to reinforce what we've known all along. *BSD is collapsing in complete disarray, as fittingly exemplified by failing dead last [samag.com] in the recent Sys Admin comprehensive networking test.

You don't need to be a Kreskin [amazingkreskin.com] to predict *BSD's future. The hand writing is on the wall: *BSD faces a bleak future. In fact there won't be any future at all for *BSD because *BSD is dying. Things are looking very bad for *BSD. As many of us are already aware, *BSD continues to lose market share. Red ink flows like a river of blood.

FreeBSD is the most endangered of them all, having lost 93% of its core developers. The sudden and unpleasant departures of long time FreeBSD developers Jordan Hubbard and Mike Smith only serve to underscore the point more clearly. There can no longer be any doubt: FreeBSD is dying.

Let's keep to the facts and look at the numbers.

OpenBSD leader Theo states that there are 7000 users of OpenBSD. How many users of NetBSD are there? Let's see. The number of OpenBSD versus NetBSD posts on Usenet is roughly in ratio of 5 to 1. Therefore there are about 7000/5 = 1400 NetBSD users. BSD/OS posts on Usenet are about half of the volume of NetBSD posts. Therefore there are about 700 users of BSD/OS. A recent article put FreeBSD at about 80 percent of the *BSD market. Therefore there are (7000+1400+700)*4 = 36400 FreeBSD users. This is consistent with the number of FreeBSD Usenet posts.

Due to the troubles of Walnut Creek, abysmal sales and so on, FreeBSD went out of business and was taken over by BSDI who sell another troubled OS. Now BSDI is also dead, its corpse turned over to yet another charnel house.

All major surveys show that *BSD has steadily declined in market share. *BSD is very sick and its long term survival prospects are very dim. If *BSD is to survive at all it will be among OS dilettante dabblers. *BSD continues to decay. Nothing short of a miracle could save it at this point in time. For all practical purposes, *BSD is dead.

Fact: *BSD is dying
[ Reply to This | Parent ]

Re:Who gives a fat fuck? *BSD is dying by Palshife (Score:-1) Tuesday October 22, @04:42PM
Re:Who gives a fat fuck? *BSD is dying by Anonymous Coward (Score:-1) Wednesday October 23, @12:28AM
FreeS/WAN and Linux (Score:0, Offtopic)
by FattMattP on Tuesday October 22, @03:14PM (#4506587)
(User #86246 Info | http://www.openpatents.org/)
When the hell is FreeS/WAN [freeswan.org] going to be merged into Linux?
[ Reply to This | Parent ]

Re:FreeS/WAN and Linux Tuesday October 22, @05:47PM
Re:FreeS/WAN and Linux Tuesday October 22, @07:06PM
Re:FreeS/WAN and Linux Tuesday October 22, @07:16PM
Re:FreeS/WAN and Linux Tuesday October 22, @07:26PM
Re:FreeS/WAN and Linux by Secure42 (Score:1) Tuesday October 22, @08:11PM
Re:FreeS/WAN and Linux by FattMattP (Score:1) Tuesday October 22, @10:02PM
Re:FreeS/WAN and Linux Thursday October 24, @07

in case the comments are slashdotted:

[Anonymous Coward]

ood (Score:-1, Offtopic)
by exspecto (exspecto2000.yahoo@com) on Sunday October 27, @10:01AM (#4541075)
(User #513607 Info) im so 1337.

fp biatches [ Reply to This | Parent ] hey (Score:0)
by Anonymous Coward on Sunday October 27, @10:01AM (#4541076) even better idea!

shut off the computer if its getting DoS'd

(FP?) [ Reply to This | Parent ] Re:hey (Score:3, Informative)
by autocracy on Sunday October 27, @10:09AM (#4541104)
(User #192714 Info | http://www.avcnet.org/jferland) That's exactly what this would do. The DDOS'd routers tell their upstream routers to cut back the flow of traffic - basically cutting out the source of the traffic. This of course requires that the upstream routers agree to do this... [ Reply to This | Parent ] Re:hey (Score:3, Informative)
by autocracy on Sunday October 27, @10:11AM (#4541113)
(User #192714 Info | http://www.avcnet.org/jferland) I'd like to withdraw/modify that statement. I read the top post too fast :)

It would shut off the source of the flood, not the destination as the original poster implied...
[ Reply to This | Parent ] *BSD can drink my *pee (Score:-1, Offtopic)
by Anonymous Coward on Sunday October 27, @10:03AM (#4541078) [ Reply to This | Parent ] Problem? (Score:1)
by prichardson (p_richardson_25@nospAm.yahoo.com) on Sunday October 27, @10:04AM (#4541081)
(User #603676 Info) Unfortunately the DDOS'ers will simply find a new way to flood a system. The best way to defend against this is to have a backup plan for when your servers get hosed. [ Reply to This | Parent ] Couldnt pushback be a Dos tool in itslf? (Score:3, Insightful)
by Anonymous Coward on Sunday October 27, @10:05AM (#4541085) If pushback is subverted, couldnt it function like an inverse DOD tool? [ Reply to This | Parent ] *BSD is dying (Score:-1, Troll)
by Anonymous Coward on Sunday October 27, @10:05AM (#4541086) It is official; Netcraft now confirms: *BSD is dying

One more crippling bombshell hit the already beleaguered *BSD community when IDC confirmed that *BSD market share has dropped yet again, now down to less than a fraction of 1 percent of all servers. Coming on the heels of a recent Netcraft survey which plainly states that *BSD has lost more market share, this news serves to reinforce what we've known all along. *BSD is collapsing in complete disarray, as fittingly exemplified by failing dead last [samag.com] in the recent Sys Admin comprehensive networking test.

You don't need to be a Kreskin [amazingkreskin.com] to predict *BSD's future. The hand writing is on the wall: *BSD faces a bleak future. In fact there won't be any future at all for *BSD because *BSD is dying. Things are looking very bad for *BSD. As many of us are already aware, *BSD continues to lose market share. Red ink flows like a river of blood.

FreeBSD is the most endangered of them all, having lost 93% of its core developers. The sudden and unpleasant departures of long time FreeBSD developers Jordan Hubbard and Mike Smith only serve to underscore the point more clearly. There can no longer be any doubt: FreeBSD is dying.

Let's keep to the facts and look at the numbers.

OpenBSD leader Theo states that there are 7000 users of OpenBSD. How many users of NetBSD are there? Let's see. The number of OpenBSD versus NetBSD posts on Usenet is roughly in ratio of 5 to 1. Therefore there are about 7000/5 = 1400 NetBSD users. BSD/OS posts on Usenet are about half of the volume of NetBSD posts. Therefore there are about 700 users of BSD/OS. A recent article put FreeBSD at about 80 percent of the *BSD market. Therefore there are (7000+1400+700)*4 = 36400 FreeBSD users. This is consistent with the number of FreeBSD Usenet posts.

Due to the troubles of Walnut Creek, abysmal sales and so on, FreeBSD went out of business and was taken over by BSDI who sell another troubled OS. Now BSDI is also dead, its corpse turned over to yet another charnel house.

All major surveys show that *BSD has steadily declined in market share. *BSD is very sick and its long term survival prospects are very dim. If *BSD is to survive at all it will be among OS dilettante dabblers. *BSD continues to decay. Nothing short of a miracle could save it at this point in time. For all practical purposes, *BSD is dead.

Fact: *BSD is dying [ Reply to This | Parent ] Re:*BSD is dying (Score:0)
by Anonymous Coward on Sunday October 27, @10:06AM (#4541089) You could at least vary the numbers in this, so as to make it APPEAR to be a valid report, different from the one you swiped it from (which also was bullshit) [ Reply to This | Parent ] Re:*BSD is dying (Score:0)
by exspecto (exspecto2000.yahoo@com) on Sunday October 27, @10:06AM (#4541093)
(User #513607 Info) hey, i havent seen the "stephen king dies" post in a while. someone post it please. i love recurring posts like this one, they remind me that people have a sense of humor. [ Reply to This | Parent ] Re:*BSD is dying (Score:2)
by Hektor_Troy on Sunday October 27, @10:10AM (#4541109)
(User #262592 Info | http://fair-use.dk/)
Due to the troubles of Walnut Creek, abysmal sales and so on, FreeBSD went out of business and was taken over by BSDI who sell another troubled OS. Now BSDI is also dead, its corpse turned over to yet another charnel house.Here's to hoping Microsoft picks up FreeBSD then. [ Reply to This | Parent ] Dealing with the loss of FreeBSD (Score:-1, Flamebait)
by Anonymous Coward on Sunday October 27, @10:07AM (#4541094) Hey, although you might not be comfortable with the thought, most people agree that FreeBSD is dying. That is an honest assessment. You really can't argue with the truth, no matter how much the truth might hurt. Truth exists independent of your personal feelings. So suck it up, put your chin up and move on. The death of FreeBSD is not the end of the world. It certainly doesn't have to be the end of your world. [ Reply to This | Parent ] Manual RegEx? (Score:1)
by stevejsmith (`slashdot' `at' `ssmith619.cjb.net') on Sunday October 27, @10:09AM (#4541103)
(User #614145 Info | Last Journal: Saturday October 26, @09:26PM)

If a large-enough site was getting DDoS'd (Yahoo!, Microsoft, universities, etc.), wouldn't there be someone on call 24/7 who could in a matter of minutes sort out what the similarities in the DDoS are and then manually get a RegEx to sort them all out?

I don't have much knowledge of the subject, but that seems like an easy want to deal with it.
[ Reply to This | Parent ] Re:Manual RegEx? (Score:1)
by mocktor on Sunday October 27, @10:16AM (#4541124)
(User #536122 Info | http://www.gothicasfuck.co.uk/) Nice idea but regex's have waaaay to high an overhead to filter the amount of traffic even a small DDoS produces - you'd need some kind of omnipotent distributed uberBeowulf cluster (or a million monkeys watching a zillion blinkenlights) [ Reply to This | Parent ] God Bless AT&T Research! (Score:-1, Troll)
by Anonymous Coward on Sunday October 27, @10:09AM (#4541106) SYSTEM V ON YOUR ASS FOO'! [ Reply to This | Parent ] Hard Times for *BSD (Score:-1, Troll)
by Anonymous Coward on Sunday October 27, @10:09AM (#4541107) So why now? Why did *BSD fail? Once you get past the fact that *BSD is fragmented between a myriad of incompatible kernels, there is the historical record of failure and of failed operating systems. *BSD experienced moderate success about 15 years ago in academic circles. Since then it has been in steady decline. We all know *BSD keeps losing market share but why? Is it the problematic personalities of many of the key players? Or is it larger than their troubled personalities?

The record is clear on one thing: no operating system has ever come back from the grave. Efforts to resuscitate *BSD are one step away from spiritualists wishing to communicate with the dead. As the situation grows more desperate for the adherents of this doomed OS, the sorrow takes hold. An unremitting gloom hangs like a death shroud over a once hopeful *BSD community. The hope is gone; a mournful nostalgia has settled in. Now is the end time for *BSD. [ Reply to This | Parent ] sure (Score:1)
by bicho on Sunday October 27, @10:15AM (#4541120)
(User #144895 Info) the best defense is the attack, so if they saturate your A/B/C network, then saturating the Internet is the obvious right solution.

Of course its not, it would do much more harm to many more innocent people.

The right solution is to educate people so that their PC's doesnt get inffected with worms and the like so they dont unknowingly contribute to DDOS.

Of course, the right is almost always the hard way and most people doesnt want to care about ignorant people so... we're in a vicious cycle here, just as in anything else. [ Reply to This | Parent ] "from the build-a-better-asshole-trap dept." (Score:0)
by Anonymous Coward on Sunday October 27, @10:15AM (#4541121) Here's a better asshole trap [goatse.cx]. [ Reply to This | Parent ] Not on linux yet? (Score:0)
by Anonymous Coward on Sunday October 27, @10:16AM (#4541127) They didn't implement with linux because linux is the operating system for stupid wannabes.
[ Reply to This | Parent ] 100 (Score:0)
by Anonymous Coward on Sunday October 27, @10:17AM (#4541128)
Who gives a fat fuck? *BSD is dying (Score:-1, Troll)
by Anonymous Coward on Tuesday October 22, @02:56PM (#4506374)
It is official; Netcraft now confirms: *BSD is dying

One more crippling bombshell hit the already beleaguered *BSD community when IDC confirmed that *BSD market share has dropped yet again, now down to less than a fraction of 1 percent of all servers. Coming on the heels of a recent Netcraft survey which plainly states that *BSD has lost more market share, this news serves to reinforce what we've known all along. *BSD is collapsing in complete disarray, as fittingly exemplified by failing dead last [samag.com] in the recent Sys Admin comprehensive networking test.

You don't need to be a Kreskin [amazingkreskin.com] to predict *BSD's future. The hand writing is on the wall: *BSD faces a bleak future. In fact there won't be any future at all for *BSD because *BSD is dying. Things are looking very bad for *BSD. As many of us are already aware, *BSD continues to lose market share. Red ink flows like a river of blood.

FreeBSD is the most endangered of them all, having lost 93% of its core developers. The sudden and unpleasant departures of long time FreeBSD developers Jordan Hubbard and Mike Smith only serve to underscore the point more clearly. There can no longer be any doubt: FreeBSD is dying.

Let's keep to the facts and look at the numbers.

OpenBSD leader Theo states that there are 7000 users of OpenBSD. How many users of NetBSD are there? Let's see. The number of OpenBSD versus NetBSD posts on Usenet is roughly in ratio of 5 to 1. Therefore there are about 7000/5 = 1400 NetBSD users. BSD/OS posts on Usenet are about half of the volume of NetBSD posts. Therefore there are about 700 users of BSD/OS. A recent article put FreeBSD at about 80 percent of the *BSD market. Therefore there are (7000+1400+700)*4 = 36400 FreeBSD users. This is consistent with the number of FreeBSD Usenet posts.

Due to the troubles of Walnut Creek, abysmal sales and so on, FreeBSD went out of business and was taken over by BSDI who sell another troubled OS. Now BSDI is also dead, its corpse turned over to yet another charnel house.

All major surveys show that *BSD has steadily declined in market share. *BSD is very sick and its long term survival prospects are very dim. If *BSD is to survive at all it will be among OS dilettante dabblers. *BSD continues to decay. Nothing short of a miracle could save it at this point in time. For all practical purposes, *BSD is dead.

Fact: *BSD is dying
[ Reply to This | Parent ]

Re:Who gives a fat fuck? *BSD is dying by Palshife (Score:-1) Tuesday October 22, @04:42PM
Re:Who gives a fat fuck? *BSD is dying by Anonymous Coward (Score:-1) Wednesday October 23, @12:28AM
FreeS/WAN and Linux (Score:0, Offtopic)
by FattMattP on Tuesday October 22, @03:14PM (#4506587)
(User #86246 Info | http://www.openpatents.org/)
When the hell is FreeS/WAN [freeswan.org] going to be merged into Linux?
[ Reply to This | Parent ]

Re:FreeS/WAN and Linux Tuesday October 22, @05:47PM
Re:FreeS/WAN and Linux Tuesday October 22, @07:06PM
Re:FreeS/WAN and Linux Tuesday October 22, @07:16PM
Re:FreeS/WAN and Linux Tuesday October 22, @07:26PM
Re:FreeS/WAN and Linux by Secure42 (Score:1) Tuesday October 22, @08:11PM
Re:FreeS/WAN and Linux by FattMattP (Score:1) Tuesday October 22, @10:02PM
Re:FreeS/WAN and Linux Thursday October 24, @07
[ Reply to This | Parent ]

New business-model?

[Anonymous Coward]

1: Write free software.
2: ?
3: Pushback packets.
4: Profit!

Re:New business-model?

[Anonymous Coward]

Underpants is where it's at

My take

[bobetov]

Sounds like a pretty v1.0 idea at this stage, but I'm psyched people are spending brain cycles working on DDoS and flash-flood solutions, since they're both problems that are only going to get worse.

(Gotta love the Slashdot effect getting named explicitly, eh? Nice to be part of the problem for a change... hehe.)

Seems to me the tricky part here is defining the aggregates. After reading the article, it isn't *really* a way to save your site from going down due to overload, more a way to prevent others sharing your pipe/routers from going down with you. ;-)

Which is a good goal in itself. It seems like a real tough thing to determine which of the millions of hits to www.yahoo.com (for ex.) are valid users, and which are DDoS bots. So both get restricted (net result: bots win), but the guy in the cage next to yahoo stays up.

Re:My take

[Subcarrier]

Sounds like a pretty v1.0 idea at this stage

I have to agree. They leave a lot of issues for further study. One big problem seems to be that gigabit backbone routers don't really have time to do any of this stuff. It's not much use if the back plate packet rate drops to one quarter because of having to detect and deal with flow aggregates.

Re:My take

[Anonymous Coward]

Too bad the slashdot effect didn't have a reference to wtf it is.

Kind of odd, in a technical paper, using a term without defining what it is/where it came from.

Re:My take

[Cato]

That's not true of all such routers - as long as the number of aggregates to be filtered is fairly low, it shouldn't have too much impact. Most of the filtering should be on the routers at the edge of a given provider's network, which have less work to do than the true core routers - this is similar to the DiffServ QoS model except that the core routers don't need to do anything at all, since traffic is limited on the edges.

Juniper routers do this sort of filtering and policing in hardware, and can also generate traffic stats efficiently. Other vendors have similar features - Cisco 7500 routers can have multiple VIP processors, distributing the work down to the interface cards.

The main constraint is that you need new software written, installed and debugged in these routers, which will take time and require an agreed standard across router vendors. In the short term, it's easier to use existing features such as NetFlow/cflowd for traffic stats, feeding into an existing DDoS analysis tool (e.g. the Arbor Networks ones), which then tells a router provisioning tool to reconfigure the routers. This would not be as slick or dynamic as the proposed scheme, but could be done today. It would also make it possible to have a human in the loop initially, reviewing suggested changes. This would work OK as long as management and routing traffic are assigned a separate queue on each router interface, guaranteeing enough bandwidth to make these changes in the face of a DDoS attack (something that the ACC approach would also need).

Re:My take

[Subcarrier]

If the hardware limits the number of aggregates that a core router can handle, it's fairly easy for an attacker to saturate the hardware.

Pushing the filtering all the way back to the edge nodes of the source networks may also be difficult, as detecting the aggregates is probably a lot easier than detecting individual malicious sources (you would like to leave the legitimate sources unblocked). Ultimately this would be the way to go, though. Applying ingress filtering universally to combat source address spoofing would be a good start.

Re:My take

[Cato]

A truly sophisticated attacker could probably hit the number of aggregates limit, but that's a second order issue and is unlikely to happen with current tools (as long as source addresses are not used in filters, since they are usually faked).

My suggestion for using current tools would work only in a single provider - cooperation between providers would require an IETF standard, perhaps using BGP extensions to carry requests for filtering/limiting, or perhaps using a human-checkable format for these filtering.

Whether in a single provider or not, routers are clearly less likely to melt if you can push the filtering/limiting upstream, reducing pressure on router and bandwidth resources by acting as close to the source of attack as possible.

Universal ingress filtering should be mandatory - enterprises should demand it of providers, and vice versa. There is a good RFC discussing this, 2827 - see http://www.cis.ohio-state.edu/cgi-bin/rfc/rfc2827. html

STEVEN KING IS DYING

[Anonymous Coward]

FreeBSD Gets 'Fast IPsec' Implementation | Log in/Create an Account | Top | 49 comments | Search Discussion
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The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
IP = Intellectual Property (Score:-1, Troll)
by Anonymous Coward on Tuesday October 22, @02:54PM (#4506343)
but with heavy borrowing

Wow, could the IP violations be any more blatent?
[ Reply to This | Parent ]

Who gives a fat fuck? *BSD is dying (Score:-1, Troll)
by Anonymous Coward on Tuesday October 22, @02:56PM (#4506374)
It is official; Netcraft now confirms: *BSD is dying

One more crippling bombshell hit the already beleaguered *BSD community when IDC confirmed that *BSD market share has dropped yet again, now down to less than a fraction of 1 percent of all servers. Coming on the heels of a recent Netcraft survey which plainly states that *BSD has lost more market share, this news serves to reinforce what we've known all along. *BSD is collapsing in complete disarray, as fittingly exemplified by failing dead last [samag.com] in the recent Sys Admin comprehensive networking test.

You don't need to be a Kreskin [amazingkreskin.com] to predict *BSD's future. The hand writing is on the wall: *BSD faces a bleak future. In fact there won't be any future at all for *BSD because *BSD is dying. Things are looking very bad for *BSD. As many of us are already aware, *BSD continues to lose market share. Red ink flows like a river of blood.

FreeBSD is the most endangered of them all, having lost 93% of its core developers. The sudden and unpleasant departures of long time FreeBSD developers Jordan Hubbard and Mike Smith only serve to underscore the point more clearly. There can no longer be any doubt: FreeBSD is dying.

Let's keep to the facts and look at the numbers.

OpenBSD leader Theo states that there are 7000 users of OpenBSD. How many users of NetBSD are there? Let's see. The number of OpenBSD versus NetBSD posts on Usenet is roughly in ratio of 5 to 1. Therefore there are about 7000/5 = 1400 NetBSD users. BSD/OS posts on Usenet are about half of the volume of NetBSD posts. Therefore there are about 700 users of BSD/OS. A recent article put FreeBSD at about 80 percent of the *BSD market. Therefore there are (7000+1400+700)*4 = 36400 FreeBSD users. This is consistent with the number of FreeBSD Usenet posts.

Due to the troubles of Walnut Creek, abysmal sales and so on, FreeBSD went out of business and was taken over by BSDI who sell another troubled OS. Now BSDI is also dead, its corpse turned over to yet another charnel house.

All major surveys show that *BSD has steadily declined in market share. *BSD is very sick and its long term survival prospects are very dim. If *BSD is to survive at all it will be among OS dilettante dabblers. *BSD continues to decay. Nothing short of a miracle could save it at this point in time. For all practical purposes, *BSD is dead.

Fact: *BSD is dying
[ Reply to This | Parent ]

Re:Who gives a fat fuck? *BSD is dying (Score:-1, Troll)
by Palshife (mattNO@SPAMpalshife.net) on Tuesday October 22, @04:42PM (#4507387)
(User #60519 Info | http://www.palshife.net/)
And yet, I'm installing it tonight. How odd... It just doesnt make sense.
[ Reply to This | Parent ]

Re:Who gives a fat fuck? *BSD is dying (Score:-1, Flamebait)
by Anonymous Coward on Wednesday October 23, @12:28AM (#4510406)
you're gay
[ Reply to This | Parent ]

FreeS/WAN and Linux (Score:0, Offtopic)
by FattMattP on Tuesday October 22, @03:14PM (#4506587)
(User #86246 Info | http://www.openpatents.org/)
When the hell is FreeS/WAN [freeswan.org] going to be merged into Linux?
[ Reply to This | Parent ]

Re:FreeS/WAN and Linux (Score:0)
by Anonymous Coward on Tuesday October 22, @05:47PM (#4507984)
And this has what to do with the BSD section?

Moderators on crack.
[ Reply to This | Parent ]

Re:FreeS/WAN and Linux (Score:0)
by Anonymous Coward on Tuesday October 22, @07:06PM (#4508614)
And this has what to do with the BSD section?

Fuck all, but this is slashdot, and he mentioned linux in a post that could possibly be seen to vaguely relate to the topic in a tangential manner...

Moderators on crack.

Or on Linux. What were you expecting, here?

[ Reply to This | Parent ]

Re:FreeS/WAN and Linux (Score:0)
by Anonymous Coward on Tuesday October 22, @07:16PM (#4508673)
Or on Linux. What were you expecting, here?

proper punctuation, here.
[ Reply to This | Parent ]

Re:FreeS/WAN and Linux (Score:0)
by Anonymous Coward on Tuesday October 22, @07:26PM (#4508746)
proper punctuation, here.

Eh? Further elaboration, please. Were you complaining about it, or just making an observation?

[ Reply to This | Parent ]

Re:FreeS/WAN and Linux (Score:1, Offtopic)
by Secure42 on Tuesday October 22, @08:11PM (#4509104)
(User #527416 Info | http://www.freeswan.org/)
Probably not soon, i think they are avoiding to add it to Linux Kernel to avoid some problems with cryptographic restrictions in some countries. Anyway most distributions include it in their kernels.
[ Reply to This | Parent ]

Re:FreeS/WAN and Linux (Score:1)
by FattMattP on Tuesday October 22, @10:02PM (#4509725)
(User #86246 Info | http://www.openpatents.org/)
Then maybe the Linux kernel needs to move outside of the US.
[ Reply to This | Parent ]

Re:FreeS/WAN and Linux (Score:0)
by Anonymous Coward on Thursday October 24, @07:36AM (#4520674)
FreeS/WAN will not come to vanilla Linux.
Various kernel hackers will make a new one based on the ipsec at the USAGI(ipv6) project.
[ Reply to This | Parent ]

Re:FreeS/WAN and Linux (Score:0, Offtopic)
by Anonymous Coward on Wednesday October 23, @09:08AM (#4511855)
According to recent posts on LKML, it's rather unlikely that FreeS/WAN will be merged. Much more likely, it will be something DaveM and Alexy? cook up, borrowing heavily from the USAGI IPV6 implementation. This may even include hooks for hardware acceleration.

FreeS/WAN's various 'tudes pretty much marginalized them, but, FWIW, at least one of the core team is supportive of the current effort.
[ Reply to This | Parent ]

The End of FreeBSD (Score:-1, Troll)
by Anonymous Coward on Tuesday October 22, @03:34PM (#4506780)
The End of FreeBSD
[ed. note: in the following text, former FreeBSD developer Mike Smith gives his reasons for abandoning FreeBSD]

When I stood for election to the FreeBSD core team nearly two years ago, many of you will recall that it was after a long series of debates during which I maintained that too much organisation, too many rules and too much formality would be a bad thing for the project.

Today, as I read the latest discussions on the future of the FreeBSD project, I see the same problem; a few new faces and many of the old going over the same tired arguments and suggesting variations on the same worthless schemes. Frankly I'm sick of it.

FreeBSD used to be fun. It used to be about doing things the right way. It used to be something that you could sink your teeth into when the mundane chores of programming for a living got you down. It was something cool and exciting; a way to spend your spare time on an endeavour you loved that was at the same time wholesome and worthwhile.

It's not anymore. It's about bylaws and committees and reports and milestones, telling others what to do and doing what you're told. It's about who can rant the longest or shout the loudest or mislead the most people into a bloc in order to legitimise doing what they think is best. Individuals notwithstanding, the project as a whole has lost track of where it's going, and has instead become obsessed with process and mechanics.

So I'm leaving core. I don't want to feel like I should be "doing something" about a project that has lost interest in having something done for it. I don't have the energy to fight what has clearly become a losing battle; I have a life to live and a job to keep, and I won't achieve any of the goals I personally consider worthwhile if I remain obligated to care for the project.

Discussion

I'm sure that I've offended some people already; I'm sure that by the time I'm done here, I'll have offended more. If you feel a need to play to the crowd in your replies rather than make a sincere effort to address the problems I'm discussing here, please do us the courtesy of playing your politics openly.

From a technical perspective, the project faces a set of challenges that significantly outstrips our ability to deliver. Some of the resources that we need to address these challenges are tied up in the fruitless metadiscussions that have raged since we made the mistake of electing officers. Others have left in disgust, or been driven out by the culture of abuse and distraction that has grown up since then. More may well remain available to recruitment, but while the project is busy infighting our chances for successful outreach are sorely diminished.

There's no simple solution to this. For the project to move forward, one or the other of the warring philosophies must win out; either the project returns to its laid-back roots and gets on with the work, or it transforms into a super-organised engineering project and executes a brilliant plan to deliver what, ultimately, we all know we want.

Whatever path is chosen, whatever balance is struck, the choosing and the striking are the important parts. The current indecision and endless conflict are incompatible with any sort of progress.

Trying to dissect the above is far beyond the scope of any parting shot, no matter how distended. All I can really ask of you all is to let go of the minutiae for a moment and take a look at the big picture. What is the ultimate goal here? How can we get there with as little overhead as possible? How would you like to be treated by your fellow travellers?

Shouts

To the Slashdot "BSD is dying" crowd - big deal. Death is part of the cycle; take a look at your soft, pallid bodies and consider that right this very moment, parts of you are dying. See? It's not so bad.

To the bulk of the FreeBSD committerbase and the developer community at large - keep your eyes on the real goals. It's when you get distracted by the politickers that they sideline you. The tireles

Read the rest of this comment...

[ Reply to This | Parent ]

Re:The End of FreeBSD (Score:-1, Redundant)
by Palshife (mattNO@SPAMpalshife.net) on Tuesday October 22, @04:37PM (#4507350)
(User #60519 Info | http://www.palshife.net/)
I'm installing it tonight. Thanks for the insight.
[ Reply to This | Parent ]

Re:The End of FreeBSD (Score:0)
by Anonymous Coward on Thursday October 24, @01:27AM (#4519646)
Same here, great idea!

Thx to the original poster. If all goes well, I'll be switching a lot of Linux boxes to BSD.
[ Reply to This | Parent ]

No Further Details. (Score:-1, Flamebait)
by Anonymous Coward on Tuesday October 22, @04:31PM (#4507311)
I just heard the sad news on talk radio. Troubled OS FreeBSD was found dead in a hotel room in Modesto. There were no further details. Truly a big loss for OS dilletante-dabbler troll hobbyists the world over. I miss it already :-(

not all DDoS attacks..

[Anonymous Coward]

Not all DDoS attacks are bandwidth based, they could be application level and targeted at all sorts of other resources.

Some examples:

SYN floods can exhaust incoming connection queues.

DNS floods (asking a recursive nameserver a million questions, or even asking an authoritative nameserver a million questions).

Too many HTTP requests to processor intensive dynamic content pages could deny service well before you are serving at your bw limit.

The paper kept referring to the aggregate detection algorithm only coming into effect when the bandwidth limit is being exceeded .. it would be nice if these actions could be initiated in other situations also.

Never the less, this is a promising initiative.

--Iain

Re:not all DDoS attacks..

[Shishak]

Well, If we can build a secure way of notifying the source network providers of an offending IP. Then have that network provider block that IP from sending on the Internet. We can then setup our servers to tell us when they are being attacked/flooded/poked at. Our server or IDS can then notify our distributed attack manager which can notify the source networks attack manager which can notify the edge router to drop packets.

It isn't all that complicated, it is a major pain to get every network admin and small ISP to implement something.

The simple act of filtering all outbound packets to only allow your netblock would stop forged IP attacks cold.

Re:not all DDoS attacks..

[smallfries]

These tend to all follow the pattern that you are exhausting the cpu of the target rather than its network pipe. Newer network protocols already have protection for this by making it more expensive for the client initiating the connection rather than the server receiving it. SCTP has this in place already with a crypto-based cookie puzzle to prevent SYN bombs (similar approach would work for dns too). The other question is when (or rather if) newer protocols like these will eventually replace TCP with all of its inherent problems or if the inertia (but everybody knows TCP...) of the current protocols will kill them off first.

Re:not all DDoS attacks..

[digitalsushi]

Dont forget calling your ISP's fax machine with a roll of black paper taped into a loop. We sent a kid out to a "grocery store" that day- we had no idea what was for lunch.

Re:not all DDoS attacks..

[whereiswaldo]

Well, If we can build a secure way of notifying the source network providers of an offending IP. Then have that network provider block that IP from sending on the Internet.

Wonderful. Then later we can expand the system to block at will anyone who says something we don't want to hear. We could even hook it into Microsoft Passport! It will be easy to silence people.

Re:not all DDoS attacks..

[essdodson]

I think the difference between the targets of the article, and the DoS situations you mention, is that the Internet as a whole is responsible for bandwidth based DoS attacks and it should act proactively to stop them. They're also far easier to detect.

Re:not all DDoS attacks..

[GnomeKing]

Too many HTTP requests to processor intensive dynamic content pages could deny service well before you are serving at your bw limit.

A webpage that I have written has suffered this problem on many of its mirrors...
(background, Its a very computationaly intensive page designed to work out the outcome of battles in an online game called planetarion)

Apart from upgrading the processor and imposing restrictions on the size of the computation thats requested, are there any other precautions I can take?

Re:not all DDoS attacks..

[Trinn]

Well, you might be able to pull together some sort of queue whereby the users that would normally get denied just have to wait. Try handling 502 (overloaded) errors yourself, might be a good starting point.

Stephen King, author, dead at 55

[Anonymous Coward]

I just heard some sad news on talk radio - Horror/Sci Fi writer Stephen King was found dead in his Maine home this morning. There weren't any more details. I'm sure everyone in the Slashdot community will miss him - even if you didn't enjoy his work, there's no denying his contributions to popular culture. Truly an American icon.

Re:Stephen King, author, dead at 55

[kryonD]

I just heard some sad news on talk radio - An Anonymous Coward was found dead in his Maine home this morning. There wasn't any more details, but athorities think he was hacked to death with a blunt spoon by author Stephen King. I'm sure everyone in the Slashdot community will be willing to provide an alibi for Stephen - even if you didn't enjoy his work, there's no denying his contributions to popular culture by killing this annoying f&#k. Truly a World icon.

"quench" ?

[Bowie J. Poag]

Sounds like the name of a sports drink targeted at uh....interior decorators.

Shouldn't it be "squelch" ?

Cheers,

Re:"quench" ?

[cheese_wallet]

One quenches a fire, so it's not that far off base. I do like squelch, although it makes me think of grape juice.

Re:"quench" ?

[adb]

But you probably don't want to quench a flood...

Re:"quench" ?

[smallfries]

you also quench a thirst - although normally with some kind of flood ...

Re:"quench" ?

[wilhelm]

The technique sounds a bit like an ICMP "source quench" (see RFC 896 for some earlier work on the topic), though interpreted by the intermediate routers, instead of the endpoints. So yeah, that's about the right word for it.

Pushback and You: A Trrrrrrrrrriple T Info Post

[The Trolling Troller]

Push Back Features

XL Push-back pallet racking

• Push-back racking allows pallets of varying types and sizes to be stored together, two, three or even four deep, with quick and easy access.
• Pallets are loaded in sequence onto wheeled carriers or cradles of varying heights, which are 'pushed-back' on inclined steel channels to utilise the full depth of the racking. As pallets are retrieved, those remaining roll forward into position at the picking face.
• This live storage system saves time, because trucks do not have to enter the racking for storage and retrieval, and also space as floor area for only one loading or picking face is required.
• Push-back is suitable for all types of pallet load, including in some cases inferior quality pallets, and is particularly suited to operations where space utilisation is paramount - in cold stores, for example.

Pushback Tow Tractor JG-75/100 Low Profile

The low-profile design on this aircraft pushback tug was originally designed for use on aircraft carriers. These tugs can now be seen throughout the world in corporate hangars for use with many of today's bizjets.

• Draw Bar Pull: 7500 to 10000lbs., Holland 400 Front & Rear
• Engine: Gasoline Ford 300 or Chrysler Flathead Ind 32, 6 Cyl.
• Transmission: Ford/Borg Warner FMX or Chrysler/727A
• Axles: Rockwell Standard #FAE-952-N-X2 Front Rockwell Standard, Planetary Drive #TA-268-FSH-X-17
• Steering: Sheppard/Saginaw Hydraulic Power-Assist
• Brakes: Power Rear Wheel Brakes
• Parking Brake: Mechanical
• Body: Northwestern Tractor, Welded Construction
• Length: 123.5" (Excluding Hitch)
• Width: 66"
• Height: 45"
• Weight: 10,000 lbs
• Tires: 6.00x9 Front/ 7.50x16 Rear
• Condition: Refurbished Lead Time: 4-6 Weeks

Pushback

When a player with Frenzy blocks a player with Stand Firm, a pushback result forces another block attempt just as if the Stand Firm player had moved.

see also: Frenzy Stand Firm

A player with Side Step may move into any adjacent square when he is pushed back. However, he must choose an empty square over an occupied square. If there are no empty squares, he must choose out of bounds over an occupied square. If all adjacent squares are occupied, he may choose to move into any occupied square (pushing the current occupant) that is adjacent except the square of the player who pushed him.

see also: Side Step

When a player with Horns and Frenzy is blitzing, in order to get the +1 ST bonus from horns, the blizter must move a square for each hit. (He would lose his horns bonus after the first hit against a Stand Firm player.)

see also: Horns Frenzy Blitz Stand Firm

A dice roll result of PUSHBACK (or PUSHBACK/POW with Dodge) counts as a Pushback result even though the player doesn't move. So, skills like Strip Ball and Frenzy will work against a Stand Firm player, and if hit by a Diving Tackler, a Pushback result ends the Stand Firm player's action.

see also: Stand Firm Strip Ball Frenzy Diving Tackle

A player who is pushed back into a square in which the football is lying, does NOT get to attempt to pick it up. The ball scatters.

see also: Pick Ups

When choosing the square that a player is pushed into, Empty squares must be chosen over occupied squares or out of bounds. Out of Bounds must be chosen over an occupied square. A square containing a non-Stand Firm player must be chosen over a square containing a Stand Firm player.

see also: Stand Firm

When one player is pushed into another player, the coach of the player who made the block should choose where that third player is pushed following the normal rules for choosing push back location. If this results in a player being pushed out of bounds and injured, the original blocker shall receive 2 SPP's for the Casualty IF it was an opponent.

You may be pushed out of the Tentacle TZ without rolling to escape the tentacles.

see also: Tentacles

Question....

[jwilcox154]

How does it prevent a Server from being Slashdotted?

Re:Question....

[Big Mark]

Pushback will ensure that when the /. effect happens, the server isn't overloaded by dropping connections enroute to the server rather than at the server itself.

I wonder what impact the pushback overhead will have when a server gets slashdotted, though. What if the pushback message gets dropped due to swamped routers?

Re:Question....

[Anonymous Coward]

What if the pushback message gets dropped due to swamped routers?

I was thinking the same thing. The kiddies could probably work around the system rather easily -- by simply ramping up their floods quickly enough.

" The Slashdot effect " w00t as quoted as within

[sh2kwave]

stated in the paper "The Slashdot effect" often leads to flash crowds.

I think that deserves some props to the boys running slashdot since they got themselves noted in the paper.

As well as some credit to every one that reads the pages :)./

This is worse

[greenrom]

What the paper suggests is that if a router is getting way too many packets to a specific destination address, it will tell the routers upstream to throttle packets to that destination address (drop a certain percentage of them).

How does this really help a DOS attack? The idea behind a DOS attack is to flood a server with so many packets that the server can't keep up and ends up dropping most of the packets. This paper does not provide a solution to this problem. It simply shifts where the packets are being dropped... at a router upstream instead of at the server or router at the edge of the network. The only advantage here is that other servers hanging off the router that aren't being DOSed will be unaffected.

The suggested solution also opens up a potential security hole. If you gained access to a server, it might be possible to send a packet to routers upstream and tell them to throttle bandwidth. This could be a much more effecient way of doing a DOS attack. Now instead of multiple machines on fast connections, all you really need to DOS your favorite website is a 268 and a 300 baud modem.

Re:This is worse

[Anonymous Coward]

If you read the post it is clearly pointed out that the objective is to prevent the DoS from affecting other services carried on the same network link.

There is no clear way to differentiate some forms of DDoS attacks from legitimate traffic or a traffic spike .. so you have to concede that the attacker has won that battle and interrupted their targetted service, the next step needs to be harm minimisation.

The pushback idea provides a generic method for notifying/instructing upstream carriers to drop a certain aggregate traffic flow and notify the destination of what affect that limiting is having so they can determine when to resume normal operation.

In the mean time though, you have prevented a DDoS that may be targeted at a single machine from affecting the entire network.

--Iain

Re:This is worse

[dubious9]

If you root a webserver chances are that you want people to see the changes that you make to it. Once you have control of the machine you can do much worse things than DOS it.

Besides it is much harder to break into a well protected machine, than to break into a couple of thousand nearly unprotected ones.

Re:This is worse

[Anonymous Coward]

No, it throttles packets based on whatever is common to a majority of the packets. So, if a website suddenly gets a huge number of requests for /index.html, it can throttle those and let requests for another page through unhindered. If a web server gets a huge number of identically formed packets, it can throttle those and let differently formed packets through unhindered.

You are correct when you say it shifts the site where the packets are dropped. However, you miss the whole point. The site's router determines a pattern common to an attack, and tells the routers upstream the pattern. Those routers tell their upstream routers the pattern, etc. Alone, the site's router might be overloaded. The routers two levels upstream might all be just about overloaded, but still able to let through all non-attacking traffic. If these routers all begin throttling, the site's router will no longer be overloaded. All nonattacking packets will be let through unhindered. All attacking packets will be throttled severely. If the attack picks up and the second-level-upstream routers can't handle it, they will pushback to the third-level-upstream routers, etc.

At least, that's how I understood it.

Can this be right?

[rocjoe71]

This sounds like innovation and that just can't happen on non-M$ operating systems, can it?

Back down to earth, it's mega-wicked when good ideas are developed in FreeBSD (or Linux). Developments like these come the closest to the original intents and purposes of open sourced OSes.

Re:Can this be right?

[tomstdenis]

Troll much?

Since when can you not write open and innovative software on a MS platform?

People like you give idiot-yuppie-zealots a bad name.

Tom

another idea...

[jjshoe]

while this idea is good... i often thought about the complexity of having software on every router like ntop or such setup with a tool like trace route.

what in the heck am i saying? lets say you get a syn with spoofed ip's (ask any ircop how much fun that is) you could then trace back through every router that spoofed ip came from. i realize this would tax machines quite a bit in logging and what not.

i dont think there will ever be a way to prevent any type of attack. i do think its important to have a proper response plan.

Re:another idea...

[Shishak]

There is a perfect, 100% sure way of stopping spoofed IP's. It is very easy, non-resource intensive and not being used by lazy network admins.

On every edge router you simply need to put an access-list to drop all packets not coming from your netblocks.

Edge routers going to customers you drop incoming packets not coming from your customer assigned IP. Amost EVERY edge device supports this, most support dynamic filters with RADIUS resquests. If you only allow your customers to send you data from their IP address it is impossible for them to be part of a spoofed attack.

Naughty Taco

[Anonymous Coward]

Cmdr. Taco gathered me as though I was a child and placed me on his lap. "Shhh," Cmdr. Taco whispered in my ear. His warm breath caused my skin to gooseflesh while Cmdr. Taco slowly rocked me. When my tears were finished, Cmdr. Taco asked, "All better, little one?" I nodded feeling emotionally spent. His lips nuzzled the hollow where his breath had teased. Lightly nipping and licking Cmdr. Taco whispered, "Shall we continue?" Without waiting for me to answer, Cmdr. Taco stood me up holding my forearms when I stumbled shakily. "Take off all of your clothes," Cmdr. Taco slowly inspected me from my swollen lips to torn blouse to thigh highs peeking from under my skirt. "You may leave the stockings on. They remind me of the whore that hid inside you before I made you my own--my sweet, little whore, all mine. So alone out here, with no one to worry about you being gone." Cmdr. Taco nodded his approval when I had the last of my clothes off. I blushed as his eyes touched over every curve and valley of my exposed body. I moved to cover myself, but Cmdr. Taco stopped me. "No! It is mine to look at, mine to use." His fingers ran lightly over my skin. Brushing the underside of my breasts first, then Cmdr. Taco cupped both in his hands. The pads of his thumbs circled my nipples until they hardened even more. A smile curved his lips, finally his right hand lowered and cupped my sex. His middle finger slid easily within my silken folds. "I think someone is enjoying our little game." His finger probed deeper. "Tell me how much you like it."

My tongue felt thick and useless. I could barely breath--thinking was beyond question. I rocked my hips up and back straddling his hand wantonly. I felt my juices seeping running down between his fingers and onto my quivering legs. I opened my mouth and tried to speak but no sound would come forth. My jaw moved woodenly. I nodded my head from side to side trying to explain.

"You dare to disobey me?" Cmdr. Taco asked in disbelief. Cmdr. Taco piled my clothes in my hands.

I was afraid that Cmdr. Taco would send me away for disappointing him. I pleaded with him with my eyes. I finally worked until, "Please" came out.

"Please, what whore?" Cmdr. Taco asked.

"Please, don't make me go." I whispered looking down unable to meet his eyes.

He looked startled for a moment and then laughed. "Let you go? Letting you leave here was the last thing on my mind. I wonder if you would beg to stay knowing what I plan on doing with you--to you?" His voice turned harsh. "Throw your clothes in the fire." I started to question then did as Cmdr. Taco asked. I watched as my clothes kindled and disappeared into ashes. "Do you realize what you have done?" Cmdr. Taco asked. I shook my head no. "The only way you can leave now is as you are." Cmdr. Taco looked up and down my naked body. "I think the town would be shocked to see you walk through town in the buff. Don't you agree? Our perfect little girl naked and wandering the streets, maybe I'll make you do that later. What would they think? Would they see you then as I do? A needy whore begging to be taken--to be possessed fully and completely. Reach down and tell me what you feel." Cmdr. Taco commanded.

I reached down quickly to obey. I needed to fill the need throbbing between my thighs. My palm slid through my sticky tight curls as my fingers brushed my clit than slid into my wetness. Riding the sensations, I watched his face. This man I didn't know, yet the man who knew everything about me.

"What do you feel?" Cmdr. Taco prompted me as though I was a child.

My hips moved of their own volition as I crammed my fingers in and out of my wetness. "I feel wet." I answered.

"What feels wet, my sweet?" Cmdr. Taco questioned.

"My pussy." I answered.

"All of it," Cmdr. Taco said watching my fingers disappear then reappear.

"My pussy feels so wet." I moaned.

"Why is your pussy so wet?" Cmdr. Taco asked pulling me towards him and pulling my fingers from my cunt.

I struggled for an answer. "I'm wet, because I like this."

He brought my fingers to his mouth and slowly sucked them one by one into his mouth thoroughly cleaning each one. His mouth opened and sucked the puddle of wetness in my palm. Cmdr. Taco reached up and pulled me towards him by my nipples. "Here now I taste like you. Taste yourself." My tongue met his, and Cmdr. Taco moved my fingers between our mouths. Our tongues traced my fingers and met in their seams licking each other. The changing textures, the smell of my pussy between us caused me to gush more. Cmdr. Taco moved my feet apart with his foot. Somehow seeing his shoes still on and taking in his fully clothed body made me feel even more naked. Cmdr. Taco ran his hands along the inside of my thighs, and I shivered my pleasure at his touch. I wanted him inside. I wanted him to touch my core. I needed to explode to release the pleasure Cmdr. Taco was building within me. His hands quickly became coated with my stickiness. Cmdr. Taco moved his hands over me, but never where I craved it most. "What makes you this wet?" Cmdr. Taco asked again.

"You do." I answered.

"Do you think flattery will get me to touch your clit, little one?" Cmdr. Taco chuckled.

"Please," I begged.

"Mmmmm, I do have a soft spot for begging, and you begged so prettily earlier." Cmdr. Taco pondered as if considering my request. My hips pressed forward seeking his touch. I had never been this wet before. I was steadily dripping now. My nipples ached; my pussy literally throbbed with need. "You, young lady are making a mess on my carpet."

"I'm sorry," I stammered.

"I think you shall have to be punished for making such a mess with that slutty little pussy of yours. What do you think?" Cmdr. Taco questioned.

"I'm sorry." I repeated. "I can't help it. I need it so much."

"Why do you think it is that you need it so much?" Cmdr. Taco pressed on.

"Because, I like it... because, I'm a dirty slut. I like the way you make me feel. Please touch me there." I begged.

"You are a bad girl. First making a mess on my good carpet, and then begging for me to touch you in such naughty places. You must be taught a lesson I'm afraid. Bend over my lap." Cmdr. Taco commanded.

I quickly hurried hoping Cmdr. Taco would make the throbbing need end. My breasts lay in front of his knee and my legs hung suspended in the air not quite touching the ground. His knees spread, and I felt helpless. His hand reached between my thighs and cupped my sex. I moaned my intense pleasure. "What do you want?" Cmdr. Taco asked.

"Please, please touch me." I implored.

"Touch you where? Cmdr. Taco asked.

"Touch my pussy, please." I begged biting my lip to keep from steadily begging and pleading for the touch I needed so badly.

"Good girl, you are learning. Tell me exactly what you want."

"I want your fingers inside me. I want you to rub my clit."

His hand rubbed over my dripping pussy then moved back to my ass smearing my juices over me. His hand dipped back down and coated once more. Cmdr. Taco rubbed my juices back and forth until my wetness covered me thoroughly. His finger finally sought my clit, and I all but screamed my joy. Cmdr. Taco laughed aloud at my eagerness. Cmdr. Taco circled my now distended clit then rubbed it roughly. His other hand rubbed soft circles on my backside, and then without warning smacked down sharply. I jerked crying out at the unexpected pain. His fingers circled my clit once more. His fingers plucked and twisted my clit as though it was a nipple. Then his wet hand came down once more. Cmdr. Taco slapped my bottom relentlessly. My flesh stung and burned. The wetness made the slaps ring out in the room. I whimpered torn between the peaking pleasure between my legs and the sting of my backside. I felt the walls of my pussy begin to tighten. "That's it my little slut," Cmdr. Taco urged on. "I know you would come like this." His fingers plunged in and out of my pussy as his other hand rained down on reddened behind. "Does it hurt, little one?"

"Yes," I whimpered.

"Do you want me to stop, little one?"

"No." I shook my head.

"Do you know what that means?" Cmdr. Taco asked never slowing his two hands--one sliding in and out, the other slapping up and down faster and faster.

Tears built in my eyes. "I like to be hurt." The blows became harder still my body moved up and back, my breasts swaying and slapping against his leg as Cmdr. Taco rammed roughly in and out of my body.

"Who's slut are you?" Cmdr. Taco asked.

"I'm your slut." I answered.

"What kind of slut are you?" Cmdr. Taco pushed on continuing his twin assault.

"I'm your little pain slut," I cried out as I came gushing even more.

"That's it baby, come hard for me," Cmdr. Taco coaxed running his fingers slowly now in and out coaxing me to come even more. As I lay quivering over his legs, Cmdr. Taco rubbed my bottom praising me. My pussy clenched and released convulsively. "You are so beautiful. You respond so fully." Cmdr. Taco lifted and turned me on his lap facing him. Cmdr. Taco slid his cock into me and held it there filling me. I felt so complete. I tightened around him stroking him without moving. Cmdr. Taco cupped my bottom in his hands and rocked me up and back running his cock in and out of me. Cmdr. Taco would completely fill me, and then withdraw leaving me feeling empty then filling me once more. We rocked slowly together. His mouth covered my neck then my jaw biting lightly. We kissed slowly the contrast from the earlier pell mell rush making it seem even more languid. Minutes stretched by, contended I laid my head on his chest as Cmdr. Taco unhurriedly fucked me. I felt myself building once more, and Cmdr. Taco felt it too. Cmdr. Taco pulled me tighter bouncing me up and down on his cock. Cmdr. Taco turned me and pushed my shoulders to the floor following me to the rug. His hand road the small of my back as my elbows rested on the carpet, and my ass turned up into the air. Cmdr. Taco hesitated a moment looking at my upturned ass before plunging into my pussy. "I'll save your ass for later." Cmdr. Taco promised. The thought of having his cock, any cock in my virgin ass sent me over the edge, and I came. Cmdr. Taco never slowed his pace, but continued to pound relentlessly into my gaping pussy. As I struggled to breath, Cmdr. Taco fucked me without restraint. His cock slammed into me; his balls slapped out a rhythm. Cmdr. Taco no longer spoke, but moaned and groaned his enjoyment. My elbows slipped beneath me, and my face lay pressed onto the rug. My nipples drug up and back on the carpet. The teasing pleasure quickly became pain as my sensitive nipples rubbed faster back and forth. My nipples burnt and stung. My elbows were rug burnt halfway to my forearm. When Cmdr. Taco came, I felt the hot wet splash of his come inside me, and it set off another wave of pleasure. Cmdr. Taco drew out and rubbed the sticky remains of his come on my asshole. "Later." Cmdr. Taco promised watching the gobs of come run along the crack of my ass. I lay gasping on the rug feeling thoroughly used. Cmdr. Taco ran his finger along the crack of my ass. "You are just so tempting, little one. Your mouth was so eager; your pussy was so wet, so hot, and now that sweet little ass of your is calling to me. Do you want to be my three hole girl?"

He sat on the floor and leaned back on the sofa. "Come here, little one." Cmdr. Taco beckoned. I turned and crawled towards him. "Take off my shoes." Cmdr. Taco ordered. I turned my ass towards him once more and untied his shoes and pulled them from his feet. His socks followed. I felt his hand on my ass and tensed as his finger slid down my crack and circled my asshole. I clenched without meaning to, and Cmdr. Taco sighed. Cmdr. Taco lifted and slid his pants and underwear down and off. Cmdr. Taco pulled me back towards his lap by the hair. I lay curled between his legs, my head resting on his thigh while Cmdr. Taco slowly stroked my hair. My face was inches from his cock, and I watched fascinated as his cock twitched and more come slowly trickled down the bulbous darkened head. My tongue involuntarily jutted across my lips as I thought of tasting his come. My action didn't go unmissed. "I'd hate to disappoint a lady." Mr. Kelly said sneering on the word lady. Cmdr. Taco grabbed a handful of my hair. I watched as another glob dropped from his head and fell into the dark matted hair at the base of his penis. His rough jerk reminded me to pay attention to him, and I quickly moved where Cmdr. Taco directed. Cmdr. Taco violently towed my head upward. Staring directly into my eyes, Cmdr. Taco threatened, "Keep that cat tongue in your mouth, or I will teach you what real pain is about." I nodded my compliance. "Say it!" Cmdr. Taco ground out impatiently.

"I'll...I'll keep my little cat tongue in my mouth." I promised.

"Yes, you will." Mr. Kelly nodded. Instead of the licking and lapping up of used come that I craved, Cmdr. Taco held my head firmly between his hands and rubbed my face in the gooey remains of our release. The quickly cooling come coated my entire face. Cmdr. Taco dragged first one cheek then the other through the puddle of sperm. Then face first, up and down his spent cock. I felt it begin to harden beneath me. The temptation to open my mouth--to taste was so great that I clenched me jaw against it. More than the threatened pain, I didn't want to displease Mr. Kelly. I wanted to please him more than I wanted to gratify my longing for come. I felt his seed spread through my eyebrows and eyelashes and begin to stiffen as it dried. The smell of his arousal was overwhelming, and I felt the familiar tightening in my body begin. When Cmdr. Taco was finally finished, Cmdr. Taco lifted me up into his arms. Cmdr. Taco smiled his satisfaction. "You look pretty covered in my come. I'll always remember you this way."

Re:Naughty Taco

[exspecto]

who else thought this was hilarious? why the heck doesnt it have a million replies? *shrug*

-- touched by an angel....'s dinger

I have a simpler solution

[Anonymous Coward]

Make ISPs liable for machines that they allow to connect that are periodically engaged in attempting to abuse other machines for longer than, say, 10 days.

Give ISPs an incentive to detect forged packets, portscanning, and other common signs of compromised machines at the source. Get rid of zombies at the source. Then there wouldn't be the raw material for DDoS.

In short keep machines from swinging their fists, rather than try to make the recipients more resistant to being hurt.

Re:I have a simpler solution

[FireballDWF]

One way to help "keep machines from swinging their fists" is to quickly notify their ISP when they do start attacking. http://www.mynetwatchman.com/vision.htm explains a system of currently 1478 people who submit their Firewall logs using an automated agent to a server which aggregates the data, backtraces the activity to its source, filters false alarms, and automatically sends escalation e-mails to responsible party, often the network abuse contact for the ISP which owns the netblock of the IP address.

blocking packets with forged return addresses

[wfmcwalter]

Perhaps someone more network-literate than I can answer this DDoS question, which has bothered me for some time.

I believe most DDoS attacks have the following in common:

1. DDoS zombies generally send packets with forged return addresses, as doing so greatly complicates attempts both to block packets and to track down individual zombies.
2. Machines used for DDoS attacks are almost always either corporate PCs or home PCs connected by DSL/cable. These nodes are single-homed, and as such packets emanating from them have only one initial route to the internet.

My question is this - why can't corporate IT people or their counterparts at ISPs reprogram their front-line routers (those that directly connect to individual end-user PCs) to block packets with forged return addresses? Forged addresses typically are either totally illegal or indicate a totally different net or subnet from the actual sender.

I can't see any reason why this wouldn't be a good idea - there really isn't any reason for the type of machines mentioned to ever act as true IP routers (as opposed to NATs), and it doesn't seem like this would be either hard or burdensome for the first-line routers to do.

Employing this would mean that DDoSers would be confined to forging return addresses within the zombies' own subnet, which would make both blocking and back-tracking much easier.

It's plain that this isn't done, so there must be a good reason why people much more network savvy than I haven't implemented it - what is it?

Re:blocking packets with forged return addresses

[Anonymous Coward]

This would work even better if the router could somehow tell your true IP address and when it sees you trying to forge packets, it black lists you and temporarily or permanently shuts down all traffic from that IP, logs the illegal attempt and notifies an administrator.

Re:blocking packets with forged return addresses

[dubious9]

Hmmm... good idea. I have had this idea with respect to e-mail servers and making sure each e-mail sent out had no forged information.

Basically, I guess that this would require some sort of change to IP. One solution would be so send the "front line router" a connection packet. Then have the router send you back a public key. Then whenever the client encrypts his IP address (or some other unique peice of information(MAC?) and send this along with every outgoing message.

The router could then maintain a lookup table with IP's and encrypted message to determine which ones to drop.

You might have to double the number of front line routers to handle the overhead, but I guess this would help quite a number of security related questions.

I realize there are probably a number of problems with this as I am not a security guy, but are they any reasons this basic idea wouldn't work?

Re:blocking packets with forged return addresses

[wfmcwalter]

This would work even better if the router could somehow tell your true IP address

Strictly, it needs only to figure out your true identity to do this blacklisting.

For ethernet connected devices (corporate and college LANs) the ethernet address serves this function.

I have no idea how this would be achieved with PPP (dialup) and PPPoE (some dsl).

For non PPPoE domestic broadband, one would imagine the DSLAM or DOCSIS-router-thingy would have the equivalent info (for DSL and cable respectively).

Re:blocking packets with forged return addresses

[swb]

"Good" networks prevent forged packets by doing what you suggest, dropping packets with bogus source addresses at the edge of the network or at appropriate ingress points.

I think the argument that is made for not doing this at a lot of ISPs is that with most Cisco routers its expensive as a lot of their routers can't fast switch with ACLs applied, they process switch, turning an adequate router into an inadequate packet-dropper.

It can also be a PITA to maintain -- if you put it at the very edge, like on an ISPs peering router with their upstream, it doesn't prevent in-block spoofing (eg, spoofing packets within the ISPs block). If you try to beat that on all the aggregation routers, you have a lot of ACLs to maintain; customer churn could put address blocks all over the place.

I'd argue that ISPs should make it a term of service that *their* customers ACL their edge routers; we-catch-spoofing-we-cut-you-off language.

Re:blocking packets with forged return addresses

[Cato]

This is mainly laziness - there are tools to help you do this, from Expect-based scripts up to commercial router provisioning tools (which can also be used to activate IP VPNs and QoS).

As for router capacity - Junipers don't have this problem, and if the ISP manages the CPE router on the customer site they can just push it down to that device. On a Cisco, where you have symmetric routing (probably the case for most smaller customers i.e. not dual-homed), you can just set the IP reverse-path forwarding option, which is very efficient - on each packet, the router does a routing lookup on the *source* address, as if it was trying to send a packet back to its origin. If the routing table doesn't have an entry for that source address that points out via the interface the packet was received on, the source address has been forged. This is not much overhead at all - just one more routing lookup.

For dual-homed customers, the provider has to use ACLs or perhaps a managed CPE, but ideally this would be a selling point for the ISP helping to generate cash to pay for router upgrades if needed - it safeguards the customer's network from being used to generate DDoS attacks with forged source addresses, which could save the customer from a lawsuit.

Re:blocking packets with forged return addresses

[wfmcwalter]

its expensive as a lot of their routers can't fast switch with ACLs applied ... It can also be a PITA to maintain

All true, but increasingly no defence for a lazy ISP. It's jolly inconvenient for me to stop my car at red lights, but it's my duty as a good road-using citizen to do so, even if I don't think I'll get into an accident.

if you put it at the very edge, like on an ISPs peering router with their upstream, it doesn't prevent in-block spoofing

Indeed, it's an imperfect solution, but it does give a start to a beseiged site - better they (and their downstream) block a whole ISPblock or whole ISP than go down entirely. Unfortunately, there's a selfish counterargument to this - an ISP who is a good citizen and implements blocking may (if it's subsequently used for DDoS) find itself cut off from (e.g.) yahoo or ebay - one that doesn't will get a _little_ more service, until the target itself expires.

I'd argue that ISPs should make it a term of service that *their* customers ACL their edge routers; we-catch-spoofing-we-cut-you-off language.

I'd second that - on the contract line following "thou shalt not maintain an open SMTP relay".

Re:blocking packets with forged return addresses

[Inertia Creep]

DDoS zombies generally send packets with forged return addresses [snip]

Not so. Maybe 20% of DDoS packets have forged source addresses. When you've got a network of 12,000 Slapper infected bots, you don't need to worry about obscuring the traffic's origins.

Blocking packets w/ spoofed source, or source address validation, is at best a small part of the solution.

A Slashdotter has a girlfriend!??!

[Anonymous Coward]

Wow, more newsworthy than Tablet PC!

Re:A Slashdotter has a girlfriend!??!

[Anonymous Coward]

only problem is, she has teh ugly

Old Idea

[Brew Bird]

This idea has been hashed to death for years.
The basic implementation has already been done.

What is novel and new about this paper is the suggestion that upstream routers are going to allow any tom, dick and mary to tell them what packets to throttle.

Always ass-uming that the larger switches can actually do this on the scale that is hinted at in the paper.

While issue 1 is specificly a political issue between carriers and customers, one could always point to the ease of which BGP routes are exchanged as an example of how easy this would be to do. Unfortunatly, since we are now talking about something that could effectivly put a transit provider out of business, there is no way issue number 1 will be overcome, unless the router manufactures give me the same kind of filter and ruleset technology I have for BGP. This would allow me to ignore anything I want from anyone, and would have the net affect of the feature being disabled!

as for 2, I'm sure some router manufacture has been touting this type of 'feature' on thier new multi-gig-a-bit MPLS/IP-does-everything-at-once switch. Don't believe it until it's out of the lab, guys. As many times as carriers have been screwed over by these new startups and their 'awsume powerful technology', I'm supprised anyone believes thier line of crap anymore.

It's too bad DDOS attacks don't go on for weeks, then we could use something like RBL to deal with it. Since they are so transitory, blackholing on the fly, (which is basicly what this paper is advocating) would require a lot more thinking about than has been put into this work.

Perhaps, instead of trying to complicate our lives with Yet Another New Protocol, you could simply come up with and IDS concatonation system, that puts together 'lists' of known DDOS sources at the current moment, and put it into a BGP feed... What a concept! Taking 2 technolgies that are known to work, and available to ANYONE that does BGP on the internet, and making it work!

Thank You, Come Again.

Re:Old Idea

[bigberk]

Perhaps, instead of trying to complicate our lives with Yet Another New Protocol, you could simply come up with and IDS concatonation system, that puts together 'lists' of known DDOS sources at the current moment, and put it into a BGP feed... What a concept! Taking 2 technolgies that are known to work, and available to ANYONE that does BGP on the internet, and making it work!

This kind of reminds me of DShield. And I think you're right, if we could automate such an internet-wide distribute of potential DDoS participant hosts then when an attack begins, the victim could invoke "the blacklist" and hopefully cut out a big chunk of the sources.

Re:Old Idea

[smallfries]

Ok, disclaimer first - I haven't actually read the paper. That said, if you're right about:

What is novel and new about this paper is the suggestion that upstream routers are going to allow any tom, dick and mary to tell them what packets to throttle.

Then, lol. Do they really think this is a good idea in any way, shape or form?
This opens up an even worse class of DOS attack than the one that it plugs. Effectively I can clamp off your traffic by accusing you of DOS'ing a bunch of servers out there somewhere (by forging requests from those servers).

Or even worse, again by forging requests from a server I can fire off pushbacks to a large number of edge routers and close down most of your traffic from those areas.

Is there no authentication in there at all?

Re:Old Idea

[Cato]

A BGP feed will only help if you want to drop ALL traffic to a given IP prefix - the ACC proposal actually lets you limit traffic by port number as well.

Also, a BGP-only solution would only let you drop traffic, so it's not very useful for flash crowds, where the traffic is legitimate but excessive. It's also not useful where the port / prefix etc can't precisely identify only DDoS traffic - rate limiting allows some good traffic to get through while also limiting the DDoS. Blackholing != limiting (did you read the paper at all?)

I agree that this can be prototyped using existing technology (see my post elsewhere), but if this approach proves useful, a dedicated protocol would be helpful - though this could perhaps be piggybacked onto BGP using additional attributes to carry the filter and rate limit information.

Re:Old Idea

[Brew Bird]

Yes, I do understand that a BGP feed will do that. Can you think of a better incentive to have the source of the DDOS actually do something about it. (Flash crowds are another issue completely, and should be handled by the local site. I think you would be hard pressed to find any site that doesn't already have a solution for 'flash' crowds availble. If it is a regular issue, you can always Akamize... If not, there is nothing stopping you from rate limiting at the edge. Forcing the core of someone else's network to rate limit based on your arbitrary rules is totally the wrong way to deal with flash crowds, IMHO)

I actually had this argument with a few router vendors a few years ago, my argument was quite simple. When you get to the point where the core switch has enough power to do all of things that it would need to do in order to.

1) filter on src/dst/port/URL whatever
2) implement these filters into multiple OC-192 trunks connections without taking too much a % loss
3) making it scale to 'Internet' size.

You have spent more money buying the switch than if you had simply gone with an 'all or nothing' solution.

AND you achieve pretty much the same result. (from the 'I need to let paying customers use the bandwidth vs these DDOS hax0r l33t skript kiddies point of view)

This is the diffrence between someone who doesn't have to pay for implementation of a technicaly superior soltion, vs someone who has to worry about how little money is being made with these expensive switches, because everyone expects their multi-megabyte broadband connection to be $29.95 a month.

Did you REALLY think it was a coincedence so many IP backbones have gone out of business? Trying to keep up with the Jones doesn't help, and feature enhancment requests to high end switches like this only increase the complexity and cost of Internet, for dubious improvment.

Relax!

[rocjoe71]

...I was only kidding over MS' statements about their 'freedom to innovate' and how open-source is a 'threat to innovation'.

It's Sunday morning! Don't be so serious over *everything*!

People like you give knee-jerk-reactionaries a bad name.

Pushback simply moves the problem

[The Moving Shadow]

While Pushback technology can help the servers to stay online, they literally push the network load off to another branch of the network where it can congest normal networkconnections. For important servers like the nameservers that have been attacked last week - where they (btw) used a similar technique of pushing requests e.g. network data off to another part of the network - this is a good method. But you run the risk of creating congestion somewhere else on the network. So people working upstream from the attacked server will probably suffer from poor accesibility. It's just a choice what you want to sacrifice, either the targetted servers or the people upstream. But i agree this technology is a step forward towards an appropriate security answer to DDOS attacks.

Not a big problem

[Gerry Gleason]

Yes, the typical arms race situation applies, but the defenders now have some good weapons at their disposal. If the methods that implement the quench feature is robust and hard to subvert, then it is just the server that needs to be updated. Many techniques could be used to identify the sources of the attacks, including some manual help from the system operators. Over time, the demon could get very good at recognizing attacks bases on heuristics, so changes to the flooding packets or patterns might not help get around the filtering.

You're talking about DoS attacks

[Subcarrier]

You don't generally need all that many machines to do SYN flooding or overload a DNS server.

DDoS attacks are brute force by nature, designed to take down sections of the network by saturating the links.

Re:You're talking about DoS attacks

[Anonymous Coward]

You don't need that many machines to get the bandwidth for those attacks, but doing it the DDOS way might make it harder to block. If the attack is coming for one machine they can just block a single ip address.

Re:You're talking about DoS attacks

[Electrum]

You don't need that many machines to get the bandwidth for those attacks, but doing it the DDOS way might make it harder to block. If the attack is coming for one machine they can just block a single ip address.

Not for SYN floods or DNS floods. Both of those are usually done using spoofed source addresses. Of course, SYN floods are easy to deal with using SYN cookies.

A perfect tool for doing DDoS....

[wuchang]

The paper talks about pushback filters based on destination-IP based address filters. Consider a DDoS attack on a popular site such as slashdot. Pushback will affect EVERYBODY, not just the unpatched zombies. If exploited correctly, this makes for a perfect tool for the hacker to obtain a 100% denial. This is an arms race, we can't afford to give hackers our nukes, unless we make sure they can't be used against us.

Re:A perfect tool for doing DDoS....

[Corfiot]

Would you rather drop the nukes and have them NOT go off?

"Oops, sorry Mr president, it appears we shot blanks again"

Public review is how the usefulness and feasibility of research such as this are determined. Besides, there is no 100% denial in the presented scenario unless the attacker actually manages to attack from ALL incoming nodes on MOST branches of the attacked network infrastructure being traversed. It is almost certain that some good, if not poor (as defined in the paper) traffic will go through.

$.02 (That's in euros)
--Corf

You're still putting daemons in /etc?

[your f*cking mother]

Come on, kids. It's not the 80s anymore (though, I'm willing to bet the guys at AT&T Research labs aren't kids, and they actually might remember when /etc was the best place to put those things... but it's not anymore... especially not on freebsd!

Um, this isn't new.

[Mordant]

Bellovin came out with this a while ago. It's an interesting concept, but has the following practical drawbacks:

1. All the various vendors would have to implement it.

2. False positives. A new form of DoS would be to generate enough spoofed traffic to trigger this sort of thing -aimed at someone else-. Imagine your outrage when your l33t IRC buddies spoof your IP address block whilst attacking www.slashdot.com - no more imbecilic, outdated "Gee, whiz!" types of posts for you to read.

3. Oftentimes, rate-limiting via CAR, traffic shaping, or other methods consumes more CPU cycles on the routers than simply blocking the offending traffic (assuming this is possible, which depends upon the attack methodology).

The best way to combat DoS attacks generally is use strong platforms which process ACLs and other features in hardware (ensuring that your config allows those features to be processed in hardware; logging ACLs like a 'deny ip any any log' just won't cut it, these days), ensure you have the ability to 'draw off the poison' by sinkholing traffic headed for the destination by advertising a null route for it on a sinkhole router (this isn't always possible, it depends upon the target of the attck; you may not want to sinkhole all requests to your Web server, for example), ensure you have as good a traffic sniffing/IDS-type capability as possible, make use of Netflow tools like CAIDA cflowd/OSU flow-tools/Flowscan/Panoptiis/FLAVIO/Arbor Networks' Peakflow DoS, and know how to get in touch with the folks at your ISP(s) who can help with identifying the (even spoofed, via Netflow tracing) sources and blocking the offending traffic upstream of you.

If you're a commercial site, strongly consider a distributed Web site, hosted at different locations and using some sort of Global Server Load Balancing technology (GSLB; Cisco's Distributed Director and 4480 are two examples of this) to send people to different sites depending up their location, network topology-wise.

Re:Um, this isn't new.

[sh2kwave]

what about the more obvious of just blocking on a timed basis the attacking's MAC , this is unique and would force the offender to change there NIC.
This should in some form upgrade the time of the block based on the the continuing offense of the target's time spent attacking.
This would have to be implimented on a network of routers being a drawback but could most proably be a software upgrade and not a massive hardware one.

I wonder when...

[Gerald]

"The authors of the paper have an initial implementation on FreeBSD."

I wonder when the LinPushbackd, GNU Pushbackd and PHPMyPushbackd projects will appear on SF.

ipv6

[fluor2]

Doesn't IPv6 fix this? IPv6 NOW!.

Re:ipv6

[Subcarrier]

Doesn't IPv6 fix this?

No. IPv6 improves a lot of things but it doesn't fix this. Sorry.

why waste energy on this instead of going ipv6?

[O0o0Oblubb!O0o0O]

excuse me if I'm wrong, but my understanding of the matter was, that source address spoofing etc. would be gone, once ipv6 is widely used. asfaik, ipv6 would prevent lots of techniques in this context, so why waste lots of emergy/work on this, instead of actually getting people to switch to ipv6.

ipv6 has been around for some time now and is implemented in every major os (both client and server). I know that the switch to ipv6 is a big task, but the way I understand it, it would also deal with a lot of problems (including to a certain extent ddos) in context with ipv4.

please correct me if I'm wrong.

Forged Headers?

[nurb432]

If they forge the send from info wouldnt that make this idea sort of useless?

Might even reverseDOS innocent people.. id be pretty upset if that happened to me.. I might even sue if i lost revenue..

finally... a cure for Slashdotting...

[constantnormal]

in a press release by the Office of Homeland Defense, it was announced that an insidious plot by hacker terrorists had been thwarted. It seems that this subversive web site, www.slashdot.org, would trigger random DDOS attacks on targets identified on their web site. It has yet to be ascertained what their intent was, as no logical pattern has been detected. The investigation continues.

Welcome to the Twilight Zone.
I certainly hope the filters used to detect true DDOS attacks are effective enough to prevent this scenario.

Re:finally... a cure for Slashdotting...

[Anonymous Coward]

It has yet to be ascertained what their intent was, as no logical pattern has been detected

I thought Jon Katz had stopped submitting stories ...

Re:finally... a cure for Slashdotting...

[vsprintf]

I thought the article was sort of insulting the way it referred to us as a "flash crowd" rather than a slash crowd.

Re:finally... a cure for Slashdotting...

[AJWM]

The term "flash crowd" goes back waaay before Slashdot ever existed (1973). It was coined by Larry Niven in a short story of that name (concerning *actual* crowds in an era where teleport booths are as ubiquitous as phone booths).

Re:finally... a cure for Slashdotting...

[vsprintf]

It was a joke. Sorry, should have included an emoticon or something. I believe I've read everything Niven published, and I really doubt they are using the term in that fashion.

Criticism, improvement and easy testing!

[bigberk]

Criticism: By giving smaller routers the power to command the behaviour of larger routers upstream, you are dangerously opening up a loophole that could allow someone in control of a router to maliciously affect upstream behaviour (potentially a huge scope!).

Improvement: Only allow routers to pushback/command up one or two hops to limit the scope of potential reverse-DoS attacks.

Easy testing: This doesn't refer to the above issue, but still... have AT&T set up a test site running their BSD implementation and then post a story to slashdot to have us test it out :)

Good concept, won't work long?

[tuxlove]

My firewall blocks all incoming ICMP except a few select types. Quench is not one of them. It could conceivably be used against you, so I block it. Why wouldn't the guys who write the scripts for the kiddies make changes to their code so that zombie machines ignore source quench ICMP?

I'm not sure how effective source quench is against routers in the path of a zombie host.

Heh heh

[tuxlove]

What if the script kiddies attacked their targets with loads of source quench packets? Can you source quench a source quench attack? :)

More than 1 source

[woogieoogieboogie]

A DDoS attack usually involves unwilling or unknowing participants. This technology will do little more than knock out a few innocent computers and cause havoc at the ISP's when people are demanding to know why their "internet broke"

Flaws in this proposal

[Animats]

This is a promising idea, but not totally effective. It protects the network, not the destination. The current implementation effectively blocks all inbound traffic for a given IP address. This kicks the target IP address off the net, which in itself is a denial of service. This approach could even make an attack against a host more effective, by shutting off all its incoming traffic. It just limits the collateral damage of denial of service attacks. This makes sense from the telco perspective (note that it's from AT&T), but not from the hosting service perspective.

An effective solution has to identify the source nodes causing the trouble and block them, not the target. This is hard, but not impossible. The big problem is doing it for fake source IP addresses.

It may be necessary to view routing the way we now have to view mail forwarding - open relays get blocked. If a router isn't sure of the IP addresses of its input, it shouldn't be forwarding those packets. Routers that continue to do so may find themselves blocked.

Ever seen The Big Hit

[Anonymous Coward]

Well the guy's doing the DOS have a 'tracer'...now the 'good guys' have jus come up with a trace busta...so now when the 'good guys' are tracing your shit, you need a trace busta busta...

That's lame

[photon317]

In a DDoS the flood is coming from helpless slobs all over the net who didn't start it and are unaware. You're going to roundtrip that garbage traffic across the net a second time for even more congestion, and then push it at the client sending it?

If they do it right it may help a small amount in awareness, but the real answer to DDoS is that there's no good answer in the current Internet. Just like Curious Yellow, the only good answer is that OS vendors change their ways very soon and get security together, so that breakins are infrequent and require intelligent effort, as opposed to todays world of a 3-month old script off the net easily seizing 100,000 machines.

Indeed

[Anonymous Coward]

If the aggregate is "All TCP traffic from all sources directed at random addresses in a subnet" such as a smart DDOS program could easily generate, you would be fucked ... you can quench it anywhere you want, but you would just be DOSing yourself.

Until they put in a mechanism to traceback spoofed packets upstream and block them at the source nothing will help.

That or make egress filtering and a given level of security mandatory for the right to route traffic onto the internet. Those few people with their exotic spoofing VPN style network accesses are not enough of a reason to put up with spoofing IMO. The majority of spoofed traffic is used for DOS attacks.

Black Ice

[solostring]

This reminds me of Gibson's 'Black Ice'... :)

I wonder when we will start seeing automated retaliatory attacks on DDos'ers and other hacking attempts... Just think: An automated scan of the remote hostile system(s) and then sending pre-programmed attacks to those computers determined by those port scans.

If the RIAA can get away with attacking servers who are sharing copyrighted content, then couldn't a company retaliate in the same way against machines who are attacking their servers?

Could make for some interesting wars :-)

Papers about the problem...

[NNland]

This sounds like Steve Gibson's suggestion from gibson research.

I wrote a paper in a similar vein last spring about stopping ddos attacks, it's the second section of this paper. It seeks to fix the underlying problem, not create a band-aid.

try this

[trybywrench]

A properly DDOS'd router or network doesn't have the queue space to deal with control packets. Most likely they will be dropped just like the DOS'ing packets. I don't think RED ( common queueing algorithm ) differenciates between types of packets. Some sort of QOS based algorithm would be needed to ensure that control packets get highest queueing priority. But then that QOS algorithm has to be installed and working in the entire network which isn't likely.

Nah, this isn't gonna work

[GreatDave]

Most of the reasons why have been said before but to sum it up...

Sending quench packets back to the routers feeding you DDoS packets, and eventually back to the host in question, is a good idea in theory. Kinda like communism. But in practice it won't work. First of all, there are the CPU strain resources on the routers and hosts. With DDoS, you have thousands if not more hosts all banging on your router, and your router is going to get a cardio workout going through its tables and deciding what gets throttled. Secondly, the return addresses on DDoS zombie packets are forged a good 80% of the time, meaning that you'll probably only hit 2 or 3 routers upstream with your quench packets.

A better solution? Null routes come to mind, but there are the CPU issues again. I'd like to see some "technology" similar to this where a customer of a commercial ISP could modify firewall rules on the _ISP's_ router to control traffic coming into their netblock. Perhaps a few routers upstream too. This really appears to be the only logical "quick fix" at the network level for DDoS.

A better fix would be to keep those zombies from ever coming into play by nuking everyone's NT/XP boxes, but that'll have to wait until penguins or daemons rule the planet.

Re:Nah, this isn't gonna work

[OzRoy]

"A better fix would be to keep those zombies from ever coming into play by nuking everyone's NT/XP boxes, but that'll have to wait until penguins or daemons rule the planet."

I don't understand how nuking XP and NT will solve DDOS. Surely you can launch a DOS attack from linux and FreeBSD just as easily.

Re:Nah, this isn't gonna work

[GreatDave]

> I don't understand how nuking XP and NT will
> solve DDOS. Surely you can launch a DOS attack
> from linux and FreeBSD just as easily.

You might want to count the number of DDoS blackhat tools on this page if you believe that. Look how many specifically mention IIS, for one. The actions taken by most of these tools require root priveleges for most Unices (true, that's not too hard for a cracker to get provided the admin is dumb, but compare to the extremely-insecure-out-of-box state of Windows in general, and 9x and XP in particular (XP having the Raw Sockets API, which can be compared to a sign that says "use me as a zombie", and 9x having no security whatsoever).

Re:Nah, this isn't gonna work

[vjzuylen]

"...but that'll have to wait until penguins or daemons rule the planet."

For a second there I had a really disturbing vision of the future. Have you ever read At The Mountains Of Madness by H.P. Lovecraft?

Re:Nah, this isn't gonna work

[m0i]

See BGPExpert AntiDOS paper.
Why would routing to Null0 be more cpu intensive than to a physical interface? I guess some kind of hardware Null0 device could be emulated, if it becomes an issue.

Re:Nah, this isn't gonna work

[GreatDave]

Routing, whether to /dev/null|Null0|127.0.0.1 or to a real address isn't really CPU intensive at all... until you have to route hundreds of requests per millisecond. Then things start getting icky. Hardware emulation of a null interface may help... but you're still _routing_. There's still computation involved, ergo the potential for denial of service on the router. So null routes supplemented by specialized hardware are a defense, but not a solution, and as the above mentioned article says, that wouldn't work with full-scale real address spoofing.

Using this as a hacking tool

[solostring]

How would this deal against spoofed ip's?

The script kiddy would just have to send spoofed ip packets to the server with Pushback installed with an ip address of a server they want to hack. Spread this out over a number of large number compromised zombie machines, against a large number of high-bandwidthed Pushback servers, and know that their actual target is being DDOS'd by Amazon, Yahoo, Microsoft etc. etc. etc.

Ugh

[richard_willey]

Call me simple or old fashioned, however, I have an intrinsic distaste for technical solutions that require intermediate system to do real time monitoring of packet flows. Even if you are using some type of stochastic sampling, this type of implementation is still going to have a significant effect on forwarding performance. Its worth noting that 99% of all the routers out there do NOT support basic IP options. For all intents and purposes, options such as "Source Quench" or "Source Route" or "Record Route" are theoretical constructs. They are not enabled or supported in the control/management plane.

I've always been a proponent of big dumb pipes and inteligent end nodes. I probably always will be. The overhead associated with supporting intelligent intermediate nodes is simply too high.

Richard

A better idea

[Anonymous Coward]

Why not just introduce some "hard" method of trace routing? Instead of an after-the-fact hack (like the current traceroute), why not design it so you can connect to a router and ask it which router data destined for you is coming from? Do it for each one and follow the chain right up to the doorstop on the other computer.

Doesn't stop DoS itself, but makes only Distributed DoS keep you "anonymous", and even then allows the infected machines to be identified and the owners notified...

Which is where spoofing comes in

[Anonymous Coward]

There is no protocol in place to find the true originator of packets.

DDoS

[Anonymous Coward]

This is simple to fix. DDoS works because there are so many packets sent that they cannot be responded to. I say just have the router blackhole the packets. This /etc/pushbackd is nothing more than a glorified ACL. The more ACls on the router cards the more the router has to work to check. A router could be programmed to sense too many SYNs and if it canot ACK responsibly, then it just blackholes the traffic for a specified period of time... kind of like the password gone wrong. Some apps, if you fat-finger your password more than a certain amount of times, simply forbid you to attempt to login again for a specified amount of time. The logs would show the attempting IP address(es) and you could simply investigate. This goes to show that you have to have humans at most points along the way in IT. We cannot automate everything, try as we might.

One way to stop DDOS/Spam

[billcopc]

I know of one great way to stop DDOS kiddies and spammers : make it a capital offence. When we start shooting their brains out on national TV, I think they'll seriously think about a career change.

Re:One way to stop DDOS/Spam

[Anonymous Coward]

there's a *slightly* less 'explosive' way to handle this.

If you can crack the veil of anonymity of one of these script-kiddies, just send him a high-res photo of his neighbourhood with his house clearly indicated.

Scares the crap outa them!!

pushbackd?

[Anonymous Coward]

That is incorrect.
DDOSers must be shovebackd.
They must go down the stairs.

Last Post!

[alpg]

XXXVI:
The thickness of the proposal required to win a multimillion dollar
contract is about one millimeter per million dollars. If all the
proposals conforming to this standard were piled on top of each other
at the bottom of the Grand Canyon it would probably be a good idea.
XXXVII:
Ninety percent of the time things will turn out worse than you expect.
The other 10 percent of the time you had no right to expect so much.
XXXVIII:
The early bird gets the worm.
The early worm ... gets eaten.
XXXIX:
Never promise to complete any project within six months of the end of
the year -- in either direction.
XL:
Most projects start out slowly -- and then sort of taper off.
-- Norman Augustine

- this post brought to you by the Automated Last Post Generator...