Seeking Comcast Contact: need to troubleshoot packet loss and/or asymmetric routing issue between Comcast & Onvoy

Adrian Chadd adrian at
Fri Aug 3 01:09:41 UTC 2007

On Thu, Aug 02, 2007, Jim Shankland wrote:

> Linux has a nifty iptables option (clamp-mss-to-pmtu) to rewrite the
> MSS in TCP SYN packets when forwarding a packet onto a link with
> a lower MTU than the MSS in the packet.  Works like a charm.  If every
> packet forwarding device on the Internet did this, PMTUD would not be
> needed.  As is, PMTUD is simply broken, due to widespread firewall
> misconfiguration.  As in so many other cases of Internet misbehavior,
> you can avoid being part of the problem, but you can't be the solution.

.. non-TCP traffic?


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