Re: 2.4.0 tcp over firewall - no connection

Doug McNaught
2001-01-10T21:08:57Z

crosser@average.org (Eugene Crosser) writes:

> I noticed rather strange behavior: stock 2.4.0 with old ISA 3Com
> on UP compiled as UP cannot open TCP connection to hosts behind a
> firewall. E.g. it is impossible to go to http://www.etrade.com/ -
> connect just never finishes. 2.2.17 on the same hardware works
> right. 2.4.0 on SMP over PPP connection works right too. MTU
> is 1500 in both cases. In both cases, kernel is compiled with
> netfilter as modules, but those are not loaded.

Known problem, exhaustively discussed on the list, and not related
to your NIC. Disable ECN (explicit congestion notification), either
in your kernel compile or in /proc/sys/<something>.

-Doug