AT&T said Monday that reports that it had blocked access to Web site 4chan.org were true, but that it did so only to keep a denial-of-service attack lined to IP addresses connected to the site from spreading.
The blockage had some bloggers crying foul and invoking the network neutrality debate.
"AT&T temporarily blocked access to the IP addresses in question for our customers," said the company in a statement on its Web site. "This action was in no way related to the content at img.4chan.org; our focus was on protecting our customers from malicious traffic."
AT&T removed the block, "after we determined the denial-of-service threat no longer existed."
Denial of service attacks are ones that can bring a site down by flooding it with requests. Such attacks recently were believed to be the culprit in disrupting some government sites, including the FTC.
Network operators maintain they need to be able to manage their network traffic flow for just such occasions. Their critics argue that too much control can morph into anticompetitive conduct or suppression of political speech. Both sides generally agree that reasonable network management is Ok, but how reasonable is defined as the larger question.