Matt Stoller lies about site blocking

Matt Stoller has a post up at MyDD dated June 14 titled (with ironic accuracy) "Please lie to me about Net Neutrality" in which he gives the following as an example of unwarranted site blocking that shows the need for net neutrality regulations:

There's a pervasive myth that there has been no discrimination on the internet against content companies. That is simply untrue. For one, Craigslist has been blocked for three months from Cox customers because of security software malfunctions.

Back on February 23rd Authentium acknowledged that their software is blocking Craigslist but it still hasn't fixed the problem, more than three months later. That's a heck of long time to delete some text from their blacklist. And this company also supplies security software to other large ISPs.

Without net neutrality protections, cable and telecom companies will have no incentive to fix these kinds of problems. Already, it's quite difficult to even know that this is happening because they are quite easy to disguise.

However, Ray Dickenson, the VP of Product Management at Authentium, the company which makes Cox's software firewall, had already explained this problem in a post on MyDD back on June 9 when Stoller first brought this up, and it has nothing to do with a software "blacklist":

I'm SVP Product Management at Authentium, Inc. We make the branded security suites that many Internet Service Providers, including Cox Communications, offer to their subscribers. I'd like to take this opportunity to set the story straight on the Craigslist issue that some Cox subscribers have experienced.

In February, we started receiving support calls from users of our branded ESP security suite at ISPs like Cox Communications and Patriot Media. These users had problems accessing the Craigslist.org web site.
Our engineers investigated the issue and found a glitch in our firewall driver that made the Craigslist site very slow to load, or not load at all. (Technical details below)

We contacted Craigslist to learn why only the Craigslist web site was affected and also had our engineers fix the firewall driver. The fixed driver is in QA and will be part of a new release this summer. Our support team has been offering the beta firewall driver to customers who call in and are willing to try it. The support team also assists users uninstalling the software if necessary.

Authentium is dedicated to providing the best possible Internet experience for all users of our security suite, which appears under many brand names. We applaud the efforts of ISPs that go the extra mile to provide free security software to their subscribers and will continue our efforts to make the Internet experience safer and easier.

Technical details:
We found that the Craigslist.org web site sends a TCP packet with a zero-length window. A zero-length window indicates the server is experiencing congestion and cannot handle more data. Our firewall driver responds by sending data only one byte at a time, even after the server increases the TCP window size. This is the glitch we have fixed and are QA testing. Any changes to network drivers must be made carefully, tested thoroughly, and certified before general release.

Authentium's initial response to the Craigslist.org webserver is exactly as specified by RFC 793 (which describes TCP) about the proper behavior when a host to which you initiate a TCP connection specifies a window size of 0, as others have pointed out at the Save the Internet blog:

Flow Control: TCP provides a means for the receiver to govern the amount of data sent by the sender. This is achieved by returning a “window” with every ACK indicating a range of acceptable sequence numbers beyond the last segment successfully received. The window indicates an allowed number of octets that the sender may transmit before receiving further permission.

The bug here is that when the Craigslist.org host later attempts to increase the window size, the Authentium software fails to do so.

It's a bug in Authentium, but it's also arguably a bug in Craigslist.org, which also had the capability of offering a fix but has failed to do so. To characterize this as an example of discriminatory website blocking by Cox is dishonest, and to repeat the claim that this was caused by "text" in their "blacklist" after being informed otherwise is a lie.

Coming on the heel's of Stoller's YearlyKos admission of not understanding the issues and calling for personal vilification of his opponents, this makes a solid case that he's in way over his head and should not be relied upon as a source of information in the net neutrality debate.

UPDATE: Timothy Karr of Save the Internet has jumped on this bogus bandwagon on his Media Citizen blog as well as on the Save the Internet blog (already linked above with the "others have pointed out" text) and at the Free Press Action HQ blog. At the last source, Karr was clearly already informed of the cause of the issue, as he links to this fairly clear explanation from Authentium, in which the Authentium CEO, John Sharp, says that they immediately contacted Craigslist.org and made a beta fix available to their customers (including Cox customers) within a couple of weeks. For no reason I can see, Karr describes this by saying that "The CEO at the 'security software' company in question is equally opaque about the Craigslist blocking." What's opaque about the explanation, and why does he put "security software" in quotes--to suggest that this is malicious blocking?