The Real Reason Why AT&T Blocked 4Chan

SafariScreenSnapz017AT&T (s t) has finally issued a statement about the company’s unannounced blocking of certain parts of forum site 4Chan. A number of parties blamed AT&T for “censoring” the Internet, presuming that the company had blocked access because of the content on 4Chan, which can range from classless to tasteless to everything in between. In fact, AT&T said it blocked one section of the site to control a distributed-denial-of-service attack that was affecting an unnamed AT&T customer. 4Chan is, for lack of a better term, the “Wild West” of the Internet. It is an unedited, unmoderated message board that is surprisingly influential on the Net. 4Chan users have been credited with starting lolcats and RickRolling. Last year, a 4Chan user allegedly hacked into Sarah Palin’s Yahoo Mail account and posted the password on 4Chan. The site, especially its /b/ page, is an interesting place — very, very “not safe for work.”

According to a statement from the phone giant:

Beginning Friday, an AT&T customer was impacted by a denial-of-service attack stemming from IP addresses connected to To prevent this attack from disrupting service for the impacted AT&T customer, and to prevent the attack from spreading to impact our other customers, AT&T temporarily blocked access to the IP addresses in question for our customers.  This action was in no way related to the content at; our focus was on protecting our customers from malicious traffic.

Overnight Sunday, after we determined the denial-of-service threat no longer existed, AT&T removed the block on the IP addresses in question. We will continue to monitor for denial-of-service activity and any malicious traffic to protect our customers.

The story got legs on Reddit, where many commentators scorched AT&T, saying the company “censors the Internet,” and 4Chan fans formed bulletin boards to organize “retaliation” against AT&T. TechCrunch wrote that blocking a web site without notification is an “extreme breach of user trust.” Of course, the blocking evidently wasn’t over 4Chan’s content, which AT&T assures me it would never do, but instead over network protocols that were affecting other customers.

Net neutrality is all well and good, but when one particular server is negatively impacting other users, AT&T is obligated to respond. Not everyone jumped on the blame AT&T bandwagon, however. Late last night, Shon Elliott from unWired Broadband wrote on the North American Network Operators Group mailing list:

There have been a lot of customers on our network who were complaining about ACK scan reports coming from We had no choice but to block that single IP until the attacks let up. It was a decision I made with the gentleman that owns the colo facility currently hosts 4chan [sic]. There was no other way around it. I’m sure AT&T is probably blocking it for the same reason. 4chan has been under attack for over 3 weeks, the attacks filling up an entire GigE. If you want to blame anyone, blame the script kiddies who pull this kind of stunt.