Re: tg3 in 2.6.12-rc6 and Cisco PIX SMTP fixup

From: Valdis . Kletnieks
Date: Fri Jun 17 2005 - 08:07:57 EST

On Fri, 17 Jun 2005 03:47:00 +0200, Lars Roland said:
> On 6/17/05, Alejandro Bonilla <abonilla@xxxxxxxxxxxxxxxxx> wrote:
> > one question,
> >
> > Can I know what is the problem?
> >:I have 2 tg3 adapters, lots e100's and some Cisco PIX and devices.
> >
> > I can try to reproduce it and see if anyone has something to say about it.
> Yes please. As I see it. Enable smtp fixup protocol on your cisco pix
> (you will need to have a smtp server to point it to), then on some
> linux system running with a kernel greater than do a telnet to
> the smtp server that is firewalled and try to issue a smtp command.
> Note that cisco has a bug report on smtp fixup banner hiding issues in
> cisco os 6.3.4 but it should not result in the connection getting
> dropped, it also does not explain why this problem does not seam to
> exists on kernels prior to 2.6.9.

2.6.9? This rings a bell.. ;)

Does disabling TCP window scaling fix it?

echo 0 > /proc/sys/net/ipv4/tcp_window_scaling

A number of firewalls just stomp on the scaling bits - the end result is
that the perceived window size is too small to make any progress and the
connection wedges up.

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