Limiting Bandwidth Hogs on Public Wireless Nets?

arglesnaf asks: "I'm a consultant and spend a lot of time on public wireless networks at client sites (mostly hospitals / universities), coffee shops, and hotels. Quite often, the problem is that some person is running BitTorrent and eating 100% of the bandwidth. The result is that I can't get email during the day or play World of Warcraft in the hotel. I have considered sniffing and spoofing TCP resets to free up some bandwidth but need an automated way to handle new BitTorrent connections. Does anybody have any ideas on how to automate the sniff and reset strategy, or other ways to carve out a little bandwidth from hogs on public wireless?"

Comments

Steps for getting bandwidth

[Kadin2048]

Step 1: Find wireless network with SSID "linksys" or "netgear"
Step 2: Point browser at gateway
Step 3: Log in with default password
Step 4: Change channel, change SSID, enable WPA-PSK, change password.
Step 5: ???
Step 6: Profit!

That's not the question

[Kadin2048]

I think there's an assumption here that he doesn't control the WL router.

E.g., it's a public router, like in a coffeeshop or hotel, but which doesn't have any QoS set up on it, so it's being abused.

He wants a way of essentially chiseling out some room on the commons, when the other guy is already over-grazing his sheep there.

Re:That's not the question

[Ex Machina]

The excellent network attack package dsniff has a really cool utility tcpnice that may help.

Short answer: No.

[Stavr0]

I'm a consultant and spend a lot of time on public wireless networks at client sites (mostly hospitals / universities)

Get yourself an EVDO cellular modem. You can deduct it as a business expense. And stop trying to disrupt other peoples's connection.

If you have a problem with bandwidth hogs, complain to the WiFi service provider. Don't take the matter into your own hands. You are not the bandwith police, what you are doing is probably illegal.

Re:Short answer: No.

[Chanc_Gorkon]

Exactly what I was going to say. A free wifi network is NOT your network. Just because someone else is being a asshat doesn't mean you need to be one as well.

Re:Short answer: No.

[Erwos]

The guy who sent in the question may not appreciate EVDO or HSDPA, because, IIRC, latencies are much higher. While this isn't a big deal for web or email usage, it's going to be painful on WoW.

Then again, if the business is paying for it, that's quite acceptable.

Re:Short answer: No.

[arglesnaf]

What you find many times if you talk to a Hotel Manager or Coffee shop owner they realize it is a problem and have no way to deal with it. They will tell you they wish they had an easy way to throttle these people, without investing in things like inline IPS / bandwidth management.

Most of my clientel is small city midwest, and EVDO is not an option.

At the hospital I am at today the IT security people think it is a great idea. Since they outsource their wireless management and the provider refuses to deal with it, they think using a wireless IPS like solution to limit hogs is their only way to fix it.

I came up with the idea to ask slashdot after talking to my Hospital client and the manager of the hotel I normally stay at. Abusing the network by eating all the bandwidth is not someones right, and not all wireless providers are capeable of ensuring equitable wireless access.

Re:Short answer: No.

[Primis]

Then again *still*, whether he can play WoW or not in a hotel is a rather stupid, frivilous issue and one not even worth commenting on. That alone speaks to the original question poster's mentality, right there, that it is somehow a "priority" over everyone else's traffic...

Re:Short answer: No.

[Vellmont]

Exactly what I was going to say. A free wifi network is NOT your network. Just because someone else is being a asshat doesn't mean you need to be one as well.

Well, my argument would be it's not the bandwidth hogs network either. If someone were blasting really loud music in a public space, would anyone but the music blaster complain if you were able to send sound cancelling noise to block the loud music (and do it in a perfect way that only stopped the loud music)?

In this case the guy isn't being an "asshat" at all since he's also making the network useable for everyone. I'd be more worried about legal implications of doing this than someones strange morality of being against inteferring with other peoples breaking of a network.

Re:Short answer: No.

[arglesnaf]

I already have spoken to management. The hospital wants to deploy whatever solution I come up with here, the hotel is supportive. One person can literally kill the connection, to the point you can't load google. This is not a question of policing, its a question of making wireless usable at all.

Re:Short answer: No.

[ArsonSmith]

Umm, that wasn't the only spelling error you had.

Just an FYI.

Re:Short answer: No.

[CXI]

I have considered sniffing and spoofing TCP resets to free up some bandwidth but need an automated way to handle new BitTorrent connections. Does anybody have any ideas on how to automate the sniff and reset strategy, or other ways to carve out a little bandwidth from hogs on public wireless?"

When you want to know about the correct way to do it, you ask about QoS and other bandwidth limiting methods. You do NOT, as you've done, talk about TCP resets and "automated sniff and reset strategy".

Re:What if you're the network admin?

[Yonder Way]

Use OpenBSD as your gateway OS and set up queues so that BitTorrent is allowed on its well known ports, but carve out dedicated bandwidth as well for other services like imap, smtp, http, https, etc. to make sure they always have priority over torrents. You can prioritize the queues so that interactive services like ssh and http/https will pre-empt bandwidth from bulk transfer services like BitTorrent and ftp. The amount of control you have with pf is any geek's dream. You can even go so far as to say that hosts running Windows get put in a lower priority queue than hosts running anything else. :)

I suggest

[Acy James Stapp]

You go from room to room asking if anyone is running bittorrent. When you find someone who is, shoot them and close bittorrent. I think any judge would consider this reasonable, after all it's *your* bandwidth they're stealing, and clearly thoes denied their WoW fix can't be expected to behave entirely rationally.

Comment removed

[account_deleted]

Comment removed based on user account deletion

Barter consulting time for services

[davidwr]

Step 1: Find a solution you could impliment cheaply if only you had permission.
Step 2: Buy the coffee shop or hotel manager lunch. Explain that they have a problem and that you are willing to fix it in exchange for goods and services. Explain how this will make life better for all their customers.
Step 3: After getting permission, fix the problem.
Step 4: Enjoy the coffee or free room-nights.
Step 5, required in some countries :( : Pay self-employment taxes on value of bartered goods.

Step 6: Use reference to get a better job than the one you have :)

um, I'm a little supprised...

[josepha48]

.. that you are asking that in public. What you are asking to do is possibly against the computer abuse and fraud act. You are asking to disrupt someone elses connection by 'hacking/cracking' thier traffic.

I'd suggest you go to the front desk and tell them that you are having problems with the wireless. That you are staying in this hotel because they have internet access. I'd suggest that you tell them someone needs to look into the situation or move you to another hotel. Tell them that you suspect that someone is doing something against the law ( I know running bit torent is not against the law ) and taking up all the bandwidth. Who knows you can drop in the comment, I think that someone is running an unlawful site and allowing people to download pirated movies and that the MPAA and RIAA may come after the hotel and sue them. That would get their attention.

Complaining often works!

*chuckle*

[TrebleJunkie]

...ya bitch about The Next Guy hogging your bandwidth, and yet most of you clamour for "Net Neutrality."

Irony.... glooooorious irony.

Re:*chuckle*

[bucky0]

That would be really ironic and funny if that was the argument against NN at all.

The argument about NN isn't about whether or not ISPs should be able to give certain type of traffic greater priority over the others (I.E. making VOIP take higher priority over HTTP)

The argument about NN is whether or not ISPs should be allowed to give certain organizations higher priority than others. What the submitter is talking about is prioritising HTTP over Bittorrent, which most wouldn't disagree about. What NN supporters are talking about is whether or not Comcast should be allowed to throttle back Vonage or Skype connections and give preference to their own VOIP service.

It's a small point, but significant, if you run it through your head.

-cheers

lower your mtu or go to starbucks

[ufnoise]

If you reduce your mtu, you might be able to squeeze some packets through and reduce latency. At least that is what I did when sharing a 56K modem connection. This also helps when your webbrowser is trying to download multiple images simultaneously.

Otherwise, go to Starbucks and pay $.10 cents a minute, because hardly anyone else will.

Spoof some ARP packets

[haydenth]

We used to have this problem when I lived in a house where 10-15 people shared a wireless connection and none of us had admin access to the router. We couldn't play XBOX live or anything because some asshat was downloading porn on bittorrent constantly. I used to just spoof ARP packets and have all of the traffic route through me, whereby I'd summarily kill all of his traffic and mess up his routing tables.

Okay...

[LWATCDR]

Isn't WOW a bandwidth hog?
Sort of seems like you are asking how can I kick off OTHER bandwidth hogs?
Or how do I control a free open network I don't own?

Okay...

You kids these days...

[Rob T Firefly]

It was fun getting online while travelling, back before public connectivity was widespread. I used to pack my hefty old 486 portable with a modem cord with alligator clips on the end (beige box style) and some straight pins of the type normally used for sewing. If you could stick two pins into the phone cord at different spots, one touching the "ring" line and the other touching the "tip," you could clip your modem onto those pins and get online without having to explain to some backwater motel clerk (or whoever else owned the line you were fiddling with) what BBSes and Usenet were all about, and your work would be pretty much undetectable afterward.

You kids with your wireless networks and your rock-n-roll and your hula hoops and your big pants... Get off my lawn!!

Re:You kids these days...

[Doctor Memory]

I used to pack my hefty old 486 portable

486? 486?!?!? Back in my day (about the time dirt went beta), we used the trusty old TI 765. With real acoustic couplers, none of your fancy-pants alligator clips. And everything was PRINTED on PAPER, so you had a permanent record of your telnet session to ucbvax to prove you'd been there.

You kids with your microprocessors and your CRTs and computers you can lift — GET OFF MY ROCKS!

Sounds like that's the solution.

[Kadin2048]

This seems like the closest thing to a solution I've yet seen in the thread. (I was hoping for "Stab People In The Face Wireless Protocol" but apparently it still hasn't been implemented.)

I wonder if running it slows down your own connection though, since you're constantly injecting packets into the other guy's connection.

Might he have to get another computer in order to run tcpnice, and then do his normal internet activities from another machine?

Is it just me...

[Samurai Cat!]

...or does this fellow complaining about BitTorrent users eating up bandwidth preventing him from eating up that same bandwidth playing WoW just seem... kinda... ironic? :/

If story poster were on MY wireless network...

[Khyber]

...and I caught him fucking with connections, especially MINE, I'd walk the 800+ foot radius from my router, circle around the router at that distance, find this bastard and BEAT HIS ASS.

This is not your network, pal. Quit trying to fuck it up. First come, FIRST FUCKING SERVE.

*WHIIIINE* I Can't play my life-sucking WoW because of the Pir8s on BT!!!11one.

Gimme a fucking break.

D-Link DSA-3100 works great

[transporter_ii]

It is more expensive than an old computer with OpenBSD on it, but it very simple to set up and is very easy to limit the speed of users by class.

We had a hotel with a 1.5Mb wireless connection that had a movie downloader just hammering us night and day. Not only was it killing the service for other users at the hotel, it was killing service for other users all over our wireless network.

Solution: We talked the hotel into getting a D-LINK DSA-3100. I had it installed in an afternoon, the hotel had a captive portal to boot, and everyone got a smaller but much fairer share of the bandwidth.

We have not had hardly a single issue with that hotel since the router was installed.

And note that this router replaced a semi-high-dollar secure router...that hung up under heavy traffic left and right.

Transporter_ii

I'm an Student...

[UnifiedTechs]

"I'm a Student and spend a lot of time on public wireless networks at my university, coffee shops, and hotels. Recently I have noticed the alot of disconections in my Bittorent of linux distro's I need to download for my CS thesis. The result is that I can't my thesis completed, during the day I have noticed someone playing World of Warcraft without any problems. I have considered sniffing and spoofing TCP resets to free up some bandwidth but need an automated way to handle new connections. Does anybody have any ideas on how to automate the sniff and reset strategy, or other ways to carve out a little bandwidth from hogs on the wireless sytem that my college tuition pays for?"

Example script

[autocracy]

I use these settings for iptables and tc on my network gateway box for ensuring that even when it's under heavy upload & download conditions, latency will still be low (my ssh sessions used to kind of suck). The idea is the link can always be fully utilized, no one grouping of traffic gets the entire reservation group, and things should (and have) remained fast for all. If you can't figure this out between the advanced ip routing documentation (google) and my script, get in touch with me and I'd be happy to consult for your client to implement a suitable solution.

# cat /etc/network/br0-up.sh
#!/bin/sh
#Masquerade ball!
iptables -t nat -F
iptables -t mangle -F
iptables -t nat -A POSTROUTING -o br0 -j MASQUERADE

#Setup general policing goodness
tc qdisc del dev eth0 root
tc qdisc add dev eth0 root handle 1: htb default 10
tc class add dev eth0 parent 1: classid 1:1 htb rate 365kbit

#General traffic
tc class add dev eth0 parent 1:1 classid 1:10 htb rate 120kbit ceil 365kbit prio 2
#Limit general traffic backlog
tc qdisc add dev eth0 parent 1:10 handle 100: bfifo limit 12000b

#Priority (small) traffic -- UDP, small SSH, ICMP, small ACK, SYNs
tc class add dev eth0 parent 1:1 classid 1:11 htb rate 120kbit prio 0

#Common bulk interactives
tc class add dev eth0 parent 1:1 classid 1:12 htb rate 125kbit ceil 365kbit prio 2
tc qdisc add dev eth0 parent 1:12 handle 120: sfq perturb 10

#Let iptables tag things
#Prority (small) queue
tc filter add dev eth0 protocol ip parent 1:0 prio 1 handle 1 fw flowid 1:11
#HTTP Queue
tc filter add dev eth0 protocol ip parent 1:0 prio 2 handle 2 fw flowid 1:12

#Small packets are fast packets
iptables -t mangle -A POSTROUTING -m length --length 0:128 -j MARK --set-mark 0x1
iptables -t mangle -A POSTROUTING -m length --length 0:128 -j RETURN
iptables -t mangle -A POSTROUTING -p icmp -j MARK --set-mark 0x1
#certain ports get higher traffic ratings
iptables -t mangle -A POSTROUTING -p tcp --dport 80 -j MARK --set-mark 0x2
iptables -t mangle -A POSTROUTING -p tcp --dport 443 -j MARK --set-mark 0x2
iptables -t mangle -A POSTROUTING -p tcp --dport 5190 -j MARK --set-mark 0x2
iptables -t mangle -A POSTROUTING -p tcp --sport 22 -j MARK --set-mark 0x2
iptables -t mangle -A POSTROUTING -p tcp --dport 22 -j MARK --set-mark 0x2
#DNS gets the faster lane
iptables -t mangle -A POSTROUTING -p udp --dport 53 -j MARK --set-mark 0x1