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End Of the Line for SpeakFreely: NATed to Death
Arun writes "John Walker (of AutoDesk and Fourmilab fame), primary author of SpeakFreely, has decided to EOL the program (a pioneering network telephony effort), come January 15th, 2004. He cites difficulty in maintaining a decade-old code base, lack of appropriate developer support and a fundamental change in the peer-to-peer nature of the Internet upon which SF is dependent as motivating factors behind his decision. While the last release of the program will continue to be available from SourceForge, the main web site, mailing list, and web forum will be shut down on the aforementioned date." He's got some good points too, like how once IPv6 is more common, most users probably won't go back to one address per machine. I know I enjoy the added security of a NATed firewall, and without a really good reason, I won't be quick to give it up.
You can have a good and secure firewall even without NAT, in case you didn't know..
Why did I discover this cool application in a discontinuation announcement?
I wish I had discovered it earlier.
Oh well, I can only hope that I can repent this mistake in my next life.
Can you hear me now? Hello? Hello?
I used this software several years ago. While it does exactly what it does, the biggest problem was the sever lack of an installed base. Once Yahoo started integrating voice chat into their IM client, I really had no use for it. Its unfortunate though, since I always felt the sound quality was inferior on Yahoo (and the others that have since come along), but I'd imagine that was due to those clients compressing more to save bandwidth.
Children in the backseats don't cause accidents. Accidents in the back seats cause children.
SF is a great program. It's not graphical bloatware, it supports many compressions, it's somewhat modular ... I've spent countless hours getting a stable 2-way voice comm over a 33.6 dialup link, back in the days, and it actually worked at some point (the rest of the time it didn't, which prompted me to change from AOL to an Internet provider. Thanks SpeakFreely!)
:)
When I discovered I could have a voice converstaions with anybody in the world, I was so excited I picked up my phone to tell my friend in Canada
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
NAT is about address use, not security. In no way should NAT ever be confused with security, even if it appears to give you some security.
Every single security feature you like about NAT can also be had without NAT.
The common things people think they get with nat:
- Connections that must initiate from inside the network.
This is easily achieved with a normal firewall and routable addresses as well.
- My addresses aren't routable, so I'm more secure.
No, your addresses are perfectly routable, just the internet at large does not route them by agreement. Your ISP could easily configure it's routers to get traffic in to your network on those addresses.
- It hides the real addresses of my machines.
Not really... or more accurately, to an outside attacker, those addresses dont mean anyhting anyway. Whether they are known or not is not relevant. A firewall in front of a network of routable addresses could hide things equally well.
NAT by itslef does not reduce exposure. The best example of this would be those who configure nat in a hurry on linux 2.4 systems..... they set up an SNAT or masquerade rule in postrouting, and that's it.
That's nat, full, 100% working nat.
With absolutely no security.
The ISP could route to their internal network, no problem, making connections to whatever they want.
This is easily fixed by a few rules.. but then you are into firewalling, and not NAT at all.
192.168.0.5/16!
No...
172.18.1.3/12!
No, please, stop
10.255.255.255/8!
AAAAAHHAHAHRRRGGNO CARRIER
Fuck Beta. Fuck Dice
Just as a point of observation wrt NAT for security, I would like to note that NAT is wonderful at making your system incapable of acting as a publicaly accessible network server, but does nothing for a large percentage of the viruses and worms that exist on the internet at this time.
In fact it can be a serious problem as a significant percentage of the people with NAT on their Broadband gateway are doing little or nothing to improve their desktop security. Why be worried when the gateway will block NAT traffic for me?
I am probably preaching to the choir, but as a simple example of the flaw, you probably still get, and read e-mail, even behind your NAT firewall. If someone sends you an infected file as an attachment, (that you happen to execute, automatically or deliberately) that happens to be an IRC-Bot that will turn your workstation into a rdos center, your NAT box is unlikely to do anything to protect your PC. In fact now that the bug is running on your system, it has the potential to check for other systems in your home network that are vulnerable to various exploits that you haven't patched for, because you are "safe behind my nat firewall".
Suddenly you have multiple boxen in your network that are all accessing the internet without your awareness, and downloading whatever the bug writers have decided to have them download. It's not even remotely improbable that your NAT secured network may become a spaming source without you knowing about it.
NAT as a security tool is the network equivalent of Security through Obscurity, and is just as flawed.
-Rusty
You never know...
Here in the netherlands at least, both the major broadband providers (UPC adn KPN)give all customers a generically routable IP.
Customers using a cable modem or dsl modem get a live wild-side IP and a unique hostname such as:
node139a2z.xs4all.nl
by which they're already DNS addresable.
Most commodity OS's and even the cheap (horrific!) home-router products I've seen have port forwarding capablity,so there's really no such problem as he describes here.
Does anyone have different experience elsewhere?
The States, for instance? I'd like to hear.
Liam.
Walker also lists an entire slew of other reasons, but if he used the NAT argument as his central reason to quit, I think he's being very short-sighted. Of course, "because I don't wanna" is always a perfectly valid reason in an open source world, too.
The IETF midcom group has been working on solutions for passing media streams through NATs and other middleboxes for a few years now. One protocol, STUN, is already a standards-track RFC, and the group has other tools in progress. These tools work with the IETF multimedia suite (SDP, SIP, RTP, etc).
First off, let me say I have no idea what Speak Freely is. My comments are solely in response to some of the reasons he gives for discontinuing the program.
Had his reasoning behind discontinuing the project rested solely on his lack of time and an aging code base, I don't think I'd have an issue. Instead, he goes on to blame the NAT protocol and boxes that implement it, like the very popular cable/DSL "routers," and many of his issues seem to either misunderstand them or deliberately misstate what they can do.
He makes comments like, "Since the user no longer has an externally visible Internet Protocol (IP) address (fixed or variable), there is no way (in the general case--there may be "workarounds" for specific NAT boxes, but they're basically exploiting bugs which will probably eventually be fixed) for sites to open connections or address packets to his machine." He continues to state, "experience has shown that a large number of installed NAT boxes either cannot map an externally accessible port to an internal IP address and port, or those who install the boxes do not provide their customers adequate information to permit them to do this."
First of all, I have yet to see a NAT device that cannot statically map ports to a machine inside the local area connection. If there is one, I'd love to know about it so I can tell anyone to avoid it. Some are more rudimentary than others - like one I know about that has no UI to distinguish TCP and UDP inbound ports - but they all offer some way of mapping inbound ports.
His argument that they don't provide sufficient documentation to allow end-users to do so, and this may be the case. But if one is to discontinue development of a program based on the fact that someone else is providing poor documentation, there wouldn't be any development going on - documentation for most hardware/software products in the last 3 years or more have been horrid in my experience.
His argument that the internet is moving towards a client-server model rather than a peer to peer model is undeniable. It's been moving that way since they allowed home computers on the internet, and shouldn't be a surprise to anyone. Still, this doesn't mean the "clients" can't continue to utilize products that utilize a peer to peer architecture. He dismisses peer to peer file sharing products while overlooking the fact that they're the most successful peer to peer architecture network to exist in the history of the internet, and disproves his argument that NAT spells the end of peer to peer.
In the end, it seems he just didn't want to continue developing his program - and instead of being honest, he thought he'd use this opportunity to climb on his soapbox and make some waves by blaming NAT for the ills of the internet and the death of his program.
Why do people just love NAT ?
Is it a "superiority complex" thing ?
"Ha ha ha, I'm better than the hackers, my addresses are hidden".
or
"Hee hee, my ISP doesn't realise I'm connecting more than one PC" BONK. Yes they do.
Its a pitty these NATters don't realise
Its just breaking the Internet, killing off useful peer to peer applications like speakeasy.
Do people like screwing around with their NAT box configuration everytime they add a new P2P application ? (dumb question on slashdot I suppose).
For those that think it is wonderful, spend some time reading and understanding this RFC
RFC 2993 - Architectural Implications of NATUntil that point, you don't have an informed opinion about NAT, so you shouldn't express it.
The Internet's nature is peer to peer - 20050301_cs_profs.pdf
The best part about NAT is that I can hook up a freshly reinstalled Windows computer to it with no firewalls like Zonealarm on it, it picks up an IP and is hooked up to the internet immediately. And I don't have to worry about it instantly getting 0wn3d by MSBlaster, etc. Giving me plenty of time to download service packs, patches, drivers, software, etc. I suppose it can be done with another computer and CD-Rs, but this way is so much easier.
Also, I can have file shares open between different computers on the NATed (natted? NATted?) network, allowing for easy sharing of files. If each computer was hooked directly to the internet there would be no way I'd have ports 135-139 open for Windows file shares!
I'm not faulting NAT whatsoever, NAT is good, NAT is great..
but NAT is not security.
Perhaps my point is too subtle... let me try to put it another way.
All the security features you think you get by using NAT are actually not related to NAT at all.. they just happen to be configured along side it, and nobody ever really thinks about it. All of them are available, and work equally well, without NAT in the picture. NAT works equally well without any security features.
My point is not that "NAT devices are insecure" or that NAT is evil.. but that implying that NAT == sequrity in any way, shape, or fashion, is wrong.
There's no added security to NAT. A nat box that blocks incoming connections is no more secure than a router that blocks incoming connections.
Ipchains used to let udp packets addressed to your internal net pass through untouched. All a hacker need do is guess your internal address space (all signs point to 192.168.0.*) and he could bombard your innards with all kinds of silly shit. And most exploits are emailed/downloaded trojans, not viruses in the old sense.
What NAT is, is convenient. I have my router box equipped with NAT and DHCP. I can bring home a laptop or plug something in, and presto! I'm online. No calling ISP and asking for another IP, no hoops to jump through.
I could pay for extra IPs from my ISP, but why? I dont serve anything from home, and neither do most home and small business users - thats what colos are for.
NAT is just way too convienient and sensible. It's like just plugging a phone into an extension, vs running it's own line.
And it works 99.9% of the time for me. Transparent proxies (ya mofo i violate RFCs by even transparently proxying http, i'm fucking crazy man, crazy!!) fill the gap for the 0.999%, leaving 0.001% of stuff a pain in the ass, and I can avoid that pain in the ass stuff since it's all warez clients, err p2p applications.
So, I don't mourn the loss of SpeakFree. Open source needs to be able to adapt to survive, too. NAT is here to stay.
I don't need no instructions to know how to rock!!!!
send the subsequent data directly between the initial hosts
This is crux, isn't it? If A and B are neither NAt'd, there is no problem.
If exactly one of A and B are NAT'd, the NAT'd party connects to a port on the non-NAT'd party, and everything i s good.
If A and B are BOTH NAT'd, then they both probably have non-routable addresses. A has no knowledge of how to get to B and vice versa. The only thing about them that we (should) know is the IP address of the NAT box (assuming there is only one between them and the Internet). Therefore, the NAT boxes would have to be aware of and participate in the protocol.
NAT service developers are not going to bother with a protocol that requires special handling until it reaches critical mass (like RealAudio did some years ago). What this guy is saying is that he can't reach sustainable mass because of NAT boxes. It's catch 22.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
i just had a neat idea what if you combined the function of the speak freely relay server, to get around the NAT issue, with bit torrent, to get around the bandwidth issue.
Don't think that'd work. Bittorrent is meant to distribute files. If you're trying to stream audio, the packets need to arrive in sequential order. With BT, the machines you're connected to send pieces of the file (whatever they have), not necessarily in any particular order that makes sense for live audio.
You can accomplish anything you set your mind to. The impossible just takes a little longer.
He should have Googled before giving up
An interconnected system of networks that connects computers around the world via the TCP/IP protocol..
This means that the Internet is made up of networks which may themselves may be made up of networks, etc. These networks use a common protocol. Most would say that not every device on the network, or even every sub network on the network has to be connected to the Internet. It is quite arguable that there are benefits, both personal and for the commons, to not have every device connected to the Internet.
What is for sure is that for the Internet to run, everyone who uses it must contribute to it's well being. There has to be enough devices connected directly to the Intent to process and forward all the packets in an efficient and timely manner. I personally pay a number of services that manage such activity on my behalf. My personal machines, which are not in the primary bussiness of routing packets, are behind a NAT, which is.
Being behind a NAT allows me to manage my network with less effect on the rest of the community. There are still many security issues, and i can still flood others if I get infected, but it is a first step. I would argue that assuming every computer on every network to be directly addressable from every other computer on the every other network might not be the best design decision. It certainly fits in well with the TelCo desire to sell at least one IP per device, as they tried to do in the past with telephones, but other than that I do not see the benifit.
"She's a scientist and a lesbian. She's not going to let it slide." Orphan Black
It is not a matter of (just) static port mapping, it is more a fundamental problem in the way DNS works with Internet addressing -- or more specifically, the way way applications interact with Internet addressing. (This will no doubt invite flames from those outraged at the idea that there might be a fundamental problem/mistake in the Internet.)
More specifically, what happens when you have multiple machines behind the NAT device? How do you map the ports statically to multiple machines *and* also communicate this information to devices on the outside of the NAT device? (That is, port 80 on the NAT device maps to server1, port 81 on the NAT device maps to server2, etc.)
The key issue is that applications are using network level addressing (IP addresses) rather than application level addresses (URLs) to establish the network connection -- we have network specific information far too embedded in the applications, which is why the transition from IPv4 to IPv6 is such a nuisance. At the moment, the DNS SRV record could help with some of these matters by specifying a port number to use for a specific service and host/domain.
A better design for applications would be for them to be completely unaware of 'IP addresses' and function purely on URLs or hostnames + service name, and link to libraries or network drivers on the machine that handle the network aspects. Really -- excepting network mangement tools, what application bothers about the MAC addresses of machines or PPP negotiation details? IP addresses should not matter to the applications, either -- at that point, much of the arguments against NAT go away.
Honestly, the fact that NAT causes applications to break is more a reflection on mistakes in the architecture/application. IP packets themselves don't fall over and die just because they transition from a PPP link to wireless to ethernet to SONET to etc. The differing layers are independent of one another -- the applications have not yet been weaned off directly diddling with the IP layer.
Wierd, I keep getting sitefinder...
Rocket science is easy. Neurosurgery, now *that's* difficult.
The vulnerability lies in the "one page, one machine" paradigm. If the net operated more like (get ready for the flames) freenet then nobody (not even the RIAA) could be DDOSd into oblivion. A bittorrent sort of structure would ensure popular documents were always widely available, but the downside (of course) is that less popular content might end up lost. Of course, one can also make the argument nothing would really get lost because some archivists would specialize in retaining this info, just like projects like the wayback machine do with physical sites.
"No, your addresses are perfectly routable, just the internet at large does not route them by agreement. Your ISP could easily configure it's routers to get traffic in to your network on those addresses."
:)
Of course the ISP gets traffic in to your network even with NAT but that's how you get to surf the web.
"That's nat, full, 100% working nat.
With absolutely no security."
Seriously tho, while your ISP can easily subvert data and existing connections (and so can Verisign etc), it is nontrivial for your ISP to make new inbound connections into your network through a NAT device.
If you know how typical NATs work, it isn't that easy. (BTW Cisco calls them PATs because Cisco used to have inferior NAT solutions that didn't support IP sharing or overloading as they called it).
In the simplest case that supports multiple NAT'ed hosts, a NAT device builds a table based on outbound packets: src address, src port, dest address, dest port -> new src address, new src port, dest address, dest port.
You need a new source port because two source hosts could use the same source port.
Reply packets that match are then translated back.
Packets that don't match can't go through the device because the device just doesn't know where they should go.
Unless the device is terribly buggy you should be reasonably safe from inbound connections.
In fact with NAT, in order to allow inbound connections you need to add more code.
So with NAT having inbound connections is harder, and that is a good thing.
Coz there are some tricks you can play with IP fragments, where you get a fragment to overlap the original header on a vulnerable operating system. But if you have a reasonably recent O/S this shouldn't work anymore even on Windows.
Simple example of how it works, an inbound packet fragment goes through a firewall with an legit destination address and port and is stored in a packet buffer on the destination host. Subsequent fragments are sent and allowed through by the firewall and they overwrite/overlap the original destination port on the packet buffer, so the destination host actually ends up with a packet that connects to a service that should have been blocked by the firewall.
If you don't allow inbound connections and only allow outbound, such subversion is a lot harder, someone needs to be able to see your outbound packets as they head towards to the real destination, in order to construct suitable "inbound" packets and fragments.
So I don't see NAT dominating the Internet. I assume most people will just use a PC with two ethernet cards rather than dedicated routers and use that PC for stuff that requires incoming connections.
I suspect the author is just bitter that his stuff is not popular anymore. Even if it's possible to talk peer-to-peer, instant messangers with hosted servers are more convinient to use.
Well, its a free world, but he should have asked if anyone wants to take over the project and then forward the links to that person.
The linux box doing the NAT is also configured to route packets. On your LAN, you would configure the "default gateway" to be that box, and thus cause any packets not destined for an address in your LAN subnet to be sent to the NAT box for routing.
Imagine if a computer at your ISP had a route added to its routing table which causes 192.168.0.0/16 to be routed to your external IP address. This computer will now send any packets destined for an address in your LAN subnet to your router, which will inspect its routing table and see that, for example, 192.168.0.0/16 is to be transmitted out of interface eth0 onto your LAN.
The way you stop this is to configure the router to drop packets on your Internet-facing interface which are addressed to internal hosts. Once you do this, you are using a packet filter (ie a "firewall") in addition to NAT.
While the user can contact and freely exchange packets with sites not behind NAT boxes, he cannot be reached by connections which originate at other sites. In economic terms, the NATted user has become a consumer of services provided by a higher-ranking class of sites, producers or publishers, not subject to NAT.
Even cheap consumer firewalls allow you to accept incoming connections and run services. Furthermore, despite a lot of noise, most broadband providers do not seem to block incoming traffic; too many games and other popular software rely on it.
The only thing that NATs change is that services should be more flexible in the ports they will work with: when you have multiple machines behind a NAT box, you end up having to assign non-standard ports to services if they are being offered by multiple firewalled machines.
I agree that the trend towards relegating end users to a "client" status is disturbing, but NAT is not primarily responsible for that. Inventing bogus technical arguments will not help us reverse that trend.
But you forgot the current result is that it's not routable.
...hard to do isn't it?
g ro und/Hacking/Methods/Technical/Source_Routing/defau lt.htm
ok...someone try to reach my 10.10.10.3 machine
http://www.iss.net/security_center/advice/Under
That method will not work if you have a quality firewall. But the reason for that not working has absolutely nothing to do with the fact that you are NATing.
This is from the motd on irc.homelien.no:
"Second, we get overwhelmed by requests to add special access for
LAN parties and small businesses running NAT (for the
illiterate, if your IP address starts with 192.168. or 10., you are
probably running NAT -- and your personal freedom is severely
restricted).
Please understand; our answer will always be NO. It always has
been, and it always will be. I will try to put this in simple
terms; NAT (Network Address Translation) and similar "technologies"
(masquerading, etc) are detrimental to the Public Internet.
NAT destroys the end-to-end transparency of the Internet. If you
do not understand this or the ramifications of this, please READ
UP ON IT and make up your mind. It is a short-term, detrimental
solution to a long-term problem which is most easily solved by
USING UP ALL AVAILABLE IPV4 ADDRESSES AS SOON AS POSSIBLE to force
a transition to IPv6.
irc.homelien.no will never succumb to the incompetence of
consultants. We do, however, realize that a number of our users
actually constitute part of the technician and consultant
community. If you want to give us something in return for
providing this service, increase your awareness of the above
issues. Short and to the point. --edison, Oystein Homelien"
(irc.homelien.no is a popular server on EFnet)
And remember kids: Never trust a computer you can actually lift.