Comcast Blocks Web Browsing
An anonymous reader writes "A team of researchers have found that Comcast has quietly rolled out a new traffic-shaping method, which is interfering with web browsers in addition to p2p traffic. The smoking gun that documents this behavior are network traces collected from Comcast subscribers Internet connections. This evidence shows Comcast is forging packets and blocking connection attempts from web browsers. One has to hope this isn't the congestion management system they are touting as no longer targeting BitTorrent, which they are deploying in reaction to the recent FCC investigations."
Throttling wouldn't be so bad if you could just opt out of it. The ISP providing my home Internet connection throttles your performance by default, but if you visit one their website, you can change the settings to unthrottled, and then upload and download gigabytes and gigabytes of music and films each both with no problem. The ISP figures most people aren't going to bother changing their settings, but the people who really love file-sharing are still free to do so.
How come they still have customers? Are they a de facto monopoly? Where are the class action lawsuits and the antitrust regulations then?
Karma cannot be described by words alone.
...I wanted to have First Post but I had to find an available proxy to get through my ISP's traffic shaping technology
Does Comcast have a death wish? It sounds like something out of Dilbert.
Eclipse in the UK, since taken over by Kingston Communications, will packet shape you so hard, that even if only downloading a linux iso from p2p at 33kbps,they will disrupt all your connections, such that web browsing becomes a pre broadband experience. Don't use p2p and all plays nice again.
so nothing new in this here in the UK
When ISPs were just targetting the minority of users who use P2P (and then under the excuse of stopping piracy/ thinking of the children/ protecting us from terrrists) there would never be enough backlash from their users to stop this kind of abuse.
However if they start screwing with http, then suddenly every Joe Sixpack will be up in arms about traffic shaping, and maybe the pressure will be sufficient to actually bring about some change.
My sincere thanks, Comcast, for bringing this issue into the mainstream.
NOT COMCASTIC
Responding on behalf of hosts that don't (aren't supposed to) exist isn't necessarily a bad thing. It can save on the 45 second timeout for customers, and can help keep FW state tables smaller.
That being said.. spoofing addresses to return RST commands and etc. just SUCKS.
I wish DSL providers would improve their coverage. Many people don't have a choice of anything BUT Comcrap.
-- You can't idiot-proof anything, because they're always coming out with better idiots.
Comment removed based on user account deletion
1. It is a darn good read. Concise, short and to the point.
/. headline had me thinking one thing - but reading the article clarified my one knee jerk reaction: "You cannot browse the web - at all!?"
2. They are using firefox.
3. The Slashdot headline is not completely accurate.
The
Reading the article I got the idea that is not exactly the case...
Seven Days with Ubuntu Unity
Granted, the person on the other end of the phone doesnt know or care about such issues as net neutrality. But she did ask why I was cancelling, and she did type in my response. So hopefully someone down the line will read it. But even if they dont, at least I know that my money will not be going to a company I despise.
It can be go tiem now plees?
I upload & download tons on Comcast's network. OTOH I don't pirate software or music. Really, I make heavy use of the bandwidth given me (routine full load) and I've never received any of these notices, any sort of throttling or anything else. Is there a site with all the assumed proff of all this Comcast badness going on that I can look at?
I'd be impressed if the loudest complainers weren't some sort of thieving pirate.
Okay, I'm not specifically a network engineer, but I like to think that I'm not network stupid. To me, this would sound suspiciously like someone trying to perform a denial of service attack.
Now, I can understand being irritated at forged packets coming back as a result, but at the same time, isn't it reasonable to expect Comcast to do something to shut down connections coming from this host? Frankly, I'm a little surprised that Comcast didn't shut off the connection altogether.
Am I missing something?
Just use gopher.
The biggest objection to what Comcast was doing was that they were generating reset packets that didn't originate with either host.
Now, this article seems to say that they will generate reset packets for hosts that don't even exist on the internet. This may be a kind of throttling, but it is sill FORGERY, and shouldn't be allowed at all.
If I have nothing to hide, don't search me
How did you discover the FIOS rollout schedule for your location? I'm contemplating moving my household and I would definitely use the current/future availability of FIOS to help me choose my destination. However, I can't figure out where to look to find a map that says "This is where you can get it, this is where you can get it in 6 months, and this is where you're out of luck."
So how did you figure this out?
This is a bit off-topic, but it does have to do with comcast.
Last month I called comcast to tell them I did not want to be called, mailed, or emailed by them or any of their 'partners'. I called in response to a mailing from comcast that provided a phone number for opting out. FWIW, I have been receiving junk mail (post and electronic) from comcast encouraging me to get internet service from them, despite the fact that I have been a comcast internet customer since it was RCN.
Yesterday I received my monthly comcast bill, and on the bill was a $1.99 charge for "change of service". I called comcast, since I recalled making no changes to my service in the past decade. The telephone operator said "that charge is for when you called to opt-out of the comcast and partner mailings". She quickly followed with "we can remove that charge with a credit to your next statement".
Sigh.
$1.99 is not much, and almost not worth the time calling about it. But the attitudes and practices behind the fee are what get my goat.
I wonder what Comcast's network would look like if they spent as much money improving bandwidth as they apparently do "shaping" (damaging) the traffic already on their wires.
Urm.... have you tried setting your upload cap? My line maxes out (admittedly, UK cable) at about 600kb/s *BUT* only if i lock the upload to around the 20-25kb/s region... Allow it to go unrestricted and it'll eat all your timeslots on the cable with upload packets forcing your downstream rate to suffer...
Programming is an Art. I am an Artist. Does that mean I get to wear a daft hat?
Sending 100 syn packets per second to an invalid internet address... that would seem like a big red someone stupid is trying (or testing) a DOS syn attack flag to any ISP worth their salt. They basically were trying to create 100 outbound connection attempts per second for an extended period of time, I would be more annoyed if the ISP didn't catch something like that, only need a few hosts to build up a nice syn attack and overrun someone's tcp stack.
To me it seemed rather obvious: http://slashdot.org/comments.pl?sid=501572&cid=22882416
please someone correct me, but this appears like comcast is knocking down SYN floods. If this is the case, it is a good thing. In fact, if they stopped all connections both ways to some tool who is slamming the network with a bunch of crap at peak time for a limited time on each offense, wouldn't that be a good thing ?
Just wait till they do the same thing with TV/phone: Hundreds of channels* Free unlimited long distance** *If you watch your TV more than 20 hours a month we'll cut you off **As long as you don't place a lot of really long distance calls. Then we'll throttle them so you only get every 3rd word
"Always forgive your enemies; nothing annoys them so much." - Oscar Wilde
We synthetically generated TCP SYN packets at a rate of 100 SYN packets per second using the hping utility ... The IP Time to Live (TTL) field for these forged TCP RST packets is consistently set to 255
So, when new connection requests are issued at the rate of 100 per second, the first router is resetting some of those requests.
The application is issuing new connection requests at a prodigious rate. The router determines that this is beyond the capacity for the router, or perhaps beyond some limit imposed on that router by the internal network. Or, perhaps, it is beyond a rate parameter that is used to detect DOS attacks.
When such a limit is exceeded, there are a few reasonable responses for the router to choose from: It can drop random packets; It can drop random SYN packets; it can drop packets from the attacking host; or it can NAK/RST some of those SYN packets. All of those are legitimate router responses. The reset packets are not "forged". They are legitimate responses in the protocol. The primitive operation is called a "provider disconnect indication".
I don't see any problem in the protocol here. And, I don't see any problem in the router behavior. The router is just protecting itself and the network from overload conditions. By selecting to disconnect calls from a host that is using far more resource than other hosts, it is just protecting the other hosts from a DOS attack by that first host.
The title of the summary should be "Local routers defend agaist DOS attack".
I'm going to be an anonymous coward here because I don't want people emailing me and there is pending litigation that we have all but won. Waiting on settlement at this time.
We sued comcast. What? How? Eh?!?
Check your EULA that you signed when first getting service. If you are a business customer this REALLY affects you. Their "shaping" technology actually caused a shitload of false positives on a bunch of alarms. Our sent packets to security equipment wasn't always returned so we started to get a lot of "failure to connect". Well... a lot of what we manage are fall back systems that when they come online take over for other sites.
Well... these different locations of hardware were not able to communicate correctly because they were identified as P2P. We use encrypted packets of random data to doubly ensure that it's authentic communication.
This set off a chain of events as the shaping got worse and worse. Originally we thought it was our network code. We couldn't reproduce it and noticed our satellite connection didn't have this issue.
Our amazing network engineers took 2 months to track down the issue and it was their shaping technology blocking or resetting our connections at almost a 90% success ratio. Now while we preferred having 24/7 connections to our equipment this was no longer possible unless we altered our code significantly.
So we looked at our EULA and sure enough there was no mention of interception of data and packet shaping. In fact, our contract said they wouldn't do anything without notifying and getting our approval first.
We sued. We won. Now we're waiting judgment for lost revenue, breaking of contract etc.
I STRONGLY recommend every business out there who has remote equipment that does more than "ping" for responses and are having trouble to check your Agreement. Screw cancelling your subscription. Sue the pants off of them.
A quick solution is to just drop the RST's coming back with a TTL of 255 (something > 250 would work fine too). Unless they are sending a reset to the destination host as well, this is a quick-fix for anyone with a Linux or BSD firewall. Similar to how the Chinese firewall can be evaded.
The company IP2Location will determine not only the geographic location of your visitors, but also their ISP.
Support Right To Repair Legislation.
In the early days of the Internet (by which I mean 1981-1983, not 1997) there were ICMP Source Quench messages. This provided a way for routers to say to an end node "Slow Down." Back when I was working on congestion control, I had our TCP implementation (a modified 3COM UNET; this was before Berkeley got into TCP) set to cut down the size of the congestion window when a Source Quench was received. I took the position that Source Quench messages should be sent before the packet-drop point was reached, so that a well-behaved TCP should never have a packet dropped for congestion reasons.
This didn't catch on, though. There was concern that sending Source Quench messages would choke the network, since as the network congests, routers need to send more Source Quench messages. That sort of behavior creates an unstable condition. And coming up with a generally applicable Source Quench policy was hard. Eventually, ICMP Source Quench was deprecated.
Without Source Quench, there's not much a router can say to an end node about congestion. A router can still send ICMP Destination Unreachable messages, though. What Comcast ought to be doing if they want to reject a connection is to send back ICMP Destination Unreachable, Code 13 (communication administratively prohibited). That's a legitimate action by a router, and it makes it clear who's complaining. Some firewalls will send such messages, so they're not unheard of; however, some NAT boxes don't translate them properly, so they may not reach home clients.
But faking a TCP RST, or worse, sending an ACK for something that didn't reply at all, is just wrong.
I've been experiencing this for at least a week, exactly how the article described. I had no idea where to attribute the problem, thinking my router might be dying or something, but this is pretty clear now. I'm just glad that I'll be moving out of the Comcast area in the next few months. YAY!
Reviewing just the first hour of video games.
This crap has to come to a halt. Not just Comcast's antics, but ISPs in general. If an ISP is going to block ports, traffic shape, or otherwise impose restrictions on internet connections, they should be required to advertise those restrictions more prominently than the features of the service. It's not right to bury restrictions on page 30 of a TOS agreement. If you're going to advertise your service as 50 times faster than a dial-up connection or advertise "blazing speeds" and low prices, they should also be required to advertise their service's restrictions just as prominently or more so. The same thing goes for "unlimited bandwidth". If they're going to advertise unlimited bandwidth, they should never be able to cite excessive usage as a reason to cut someone off. Our world should not be run by marketing and PR people. "Liar" should not be a viable career path.
* for the first 6 months, then only $199.99 each month thereafter
Besides their apparent sadism by implementing filters and such (same RIAA/SCO business model, just change "Sue customers" to "prevent from using what they paid for"), Their advertised offers always have very tiny fine print, hidden in the margins and borders of the mass mailings, mentioning that oh yeh, the price quoted above in the bold 1000pt font is good only for a couple months before we double or triple it, and you are still locked in to us for a year! That is the main reason Im staying away from them. Besides, I got higher up/down bandwidth AND static IPs (something else comcast WONT do) for a MUCh cheaper price from DSL Extreme</happycustomershamelessplug>. If you sign up, feel free to use me as a referral (username there same as here).
tm
Support TBI Research: http://www.raisinhope.org
As a FiOS user (and very satisfied, aside from the port 80 blocking) I don't really care, but as a former Comcast customer and for those of you that are locked into Comcast...
Comcast has their own "Comcastic!" word for describing the Comccast experience. Why not turn it into a sarcastic meme of "fantasic!". Better yet, with specific application to losing bits.
Examples:
My Hard-drive crashed. Comcastic!
We had a Comcastic terminator on this 10base-2 cable which was causing the problem.
I sent they money, but western union got a bit Comcastic.
Steven Hawking thinks black holes have Comcastic properties.
Slashdot's rate-of-post filter: Preventing you from posting too many great ideas at once.
Except for the minor fact that the stock prices are going up...
I am an Earthlink high-speed subscriber with the "last mile" provided on Comcast Cable in the Seattle area.
I rarely notice any long-term "problems" but I and the folks running a particular website (a low volume one at that) have been working trying to find the reason I CONSTANTLY get repeated resets trying to access their site (hosted on Digital River, a local competitor...)
I don't get the resets on any other IPs, only others on Comcast get ANY, and the DR hosted site is NOT even seeing my requests.
It looks like I may just have found the "problem" and it may be Comcast blocking my access even though I am not THEIR customer directly.
Thing is, what in Hell can we do about it???
--Tomas
Perhaps the problem was that you were rooming with assholes?
They're not just sending RSTs. read teh whole article, you've got routers sending SYN/ACK packets as well, pretending to be the destination host... even when that host does not exist. That's the part that's forgery.
Of course these providers have improved their services. The problem is they have not improved them quite as well as they could have. And a lot of the ways they are "improving" them focues on ways to extract more money out of the customers, rather than providing a service that increases the value to customers. Would you expect any less of a business motived exclusively by revenue growth?
One big problem is that these companies are sitting on "gold mines" that were established for them (or for the company they bought out) through exclusive monopolies on the infrastructure. Although they invested in this infrastructure, they benefitted from government guarantees of an exclusive regulated monopoly. Now, with most of the regulation lifted, they are using this infrastructure they "inherited" to gouge customers (as opposed to supplying a regulated service that would be sufficient to pay back the investment). At the same time, they know competitors are basically unable to overbuild, not because of any exclusivity, but merely because it doesn't make sense to invest in another infrastructure (because the new builder would know they could at best get 50% of the customer base).
IMHO, the people have a "lien" in that infrastructure because of having guaranteed the exclusivity in the past. That "lien" should be exercised in the form of maintaining a level of regulation on the infrastructure that permits fair, equal, and neutral use, as well as pricing that is fair and does not gouge consumers.
It's bad enough that we have such a poor service from companies like several cable companies and many telephone companies in terms of how the internet layer services are rendered over the infrastructure. If we had fair access to the infrastructure by other providers of internet layer service, then competition would at least allow someone that does a better job to offer services, if not encourage others to do better to keep customers happy.
Long ago, AT&T was broken up between local service and long distance service because at the time it was seen that long distance would be better provided through competition. This was in fact correct and it did improve long distance through better offerings, better pricing, etc. But the split wasn't quite right in terms of today's needs. What we need today for telephone and cable service is a split that separates the ownership and management of the infrastructure, and the companies that can offer services over that infrastructure. We are already seeing this point of split taking place in many areas for electrical power service. In many areas, people can contract to get their electric power from any of a number of power providers (some that actually generate power, and some that merely buy it on the generation market). This has opened up options we would not have otherwise even seen, such as greener power preferences.
What I propose is that governments in all areas support (even financially) the development of an all new fiber based infrustructure. Instead of this being a branched fiber structure like Verizon FiOS, this infrastructure install a minimum of 4 fibers from each home (maybe more for businesses) all the way to a central office connection facility. This infrastructure, including the central office facilities, will be owned by the local government (or liened or otherwise regulated by it), and operated in a fully fair and neutral way. The home owner/renter can then acquire services from any company prepared to connect service to them through one or more of these fiber circuits. Legacy/incumbent providers of information/entertainment service like Comcast, and telco service like Verizon, can make use of this by being one of these providers. They would be able to offer any services they want through that fiber connection (which is plenty sufficient for a huge amount of service on just 1 of the 4 fibers). They could even choose to subcontract
now we need to go OSS in diesel cars
If you'd read the article, you'd know that Comcast forges the three way handshake and then sends an RST. The real destination doesn't see any traffic at all. Dropping the RST would accomplish nothing.
Reduce, reuse, cycle