[Infowarrior] - Comcast blocking more types of traffic than previously thought

[Richard Forno]

Comcast traffic blocking: even more apps, groupware clients affected

By Eric Bangeman | Published: October 21, 2007 - 11:15PM CT

http://arstechnica.com/news.ars/post/20071021-comcast-traffic-blocking-even-
more-apps-groupware-clients-affected.html

Last week, we reported on mounting evidence that Comcast is targeting and
disrupting BitTorrent traffic on its network. Further digging by interested
parties has turned up more indication that BitTorrent isn't the only popular
P2P protocol being tampered with by the United States' largest ISP.

The Electronic Frontier Foundation noticed the same sort of packet forging
that the AP did (and that Broadband Reports readers did some time ago), and
continued its testing to see if other applications are affected. The answer
is a disturbing "yes." The results of additional testing done by the EFF
indicate Comcast is sending forged reset packets with some Gnutella traffic.
When the EFF ran a Gnutella node on a Comcast connection, the forged reset
packets disrupted communication between the nodes.

What's particularly insidious about Comcast's packet forging is that it's
transparent to both its customers and those on the opposite ends of the
connection. Applications such as BitTorrent and Gnutella retain some of
their functionality, but they'll also appear to malfunction for no apparent
reason.

Even if you accept the argument that all P2P traffic is inherently evil, and
that Comcast has the right to disrupt it in order to put a stop to copyright
infringement, Comcast's traffic-shaping efforts have apparently extended
beyond the realm of P2P and into good old enterprise groupware. Kevin
Kanarski, who works as a Lotus Notes messaging engineer, noticed some
strange behavior with Lotus Notes when hooked up to a Comcast connection
last month.

When Lotus Notes users attempt to send e-mail with larger attachments over
Comcast's network, Notes will drop its connection. Instead of a successfully
sent e-mail, they're greeted with the error message, "Remote system no
longer responding." Kanarski did some digging and has managed to verify that
Comcast's reset packets are the culprit. Instead of passing the legitimate
e-mail through its network, Comcast's traffic monitoring tool (likely
Sandvine) is sitting in the middle, imitating both ends of the connection,
and sending reset packets to both client and server.

So far, Comcast has been extremely tight-lipped about what's going on here.
The only thing Comcast will admit to is using "the latest technologies to
manage our network to provide a quality experience for all Comcast
subscribers." From the look of things, that quality experience doesn't
extend to BitTorrent, Gnutella, and Lotus Notes‹and we wouldn't be surprised
to see more applications added to that list.

Whatever its methods and motivations are, Comcast's actions are giving
advocates of network neutrality legislation new ammunition. Gigi B. Sohn,
president of Public Knowledge, said that Comcast's actions demonstrate the
need for legislation. "Add this incident to the Verizon behavior on text
messaging and AT&T's censoring of the Pearl Jam concert and it's clear that
the policymakers who kept saying, 'Wait until there's a problem' before
acting on legislation to keep the Internet free and non-discriminatory have
to wait no longer," said Sohn in a statement. "We have a problem, and it's
time to act on it."

We've requested comment from Comcast on these latest developments and will
update this post as they become available.