Re: another pre-2.0.31 problem

Ruud van Hemert (
Mon, 9 Jun 1997 11:26:36 +0200 (CEST)

On 2 Jun 1997, Hauke Johannknecht wrote:

> aehm, i got a "nice" networking problem.
> i have two local ethernets (split for security) and
> dial up to my ISP via ISDN (HDLC, snycPPP).
> both networks and the isdn are connected to a
> masqerading router/firewall.
> 386-dx-40, 8mb ram, 2x cheap-o-ne2000, 1x teles 16.3;
> everything works fine localy, and even the isdn pretends to work most times.
> i can irc around, use the WWW, use ftp, play quake ...
> all from a masqed host. but when i try to send more than
> a hand full of data (ftp-put-command, dcc-send, news-suck
> trying to post a BIG article, ...) the router panics away.
> > Kernel panic: skpush:under: <somewhere>:2
> > In swapper task - not syncing
> btw, this is 100% repro at least since
> kernel 2.0.27 ! ... (took some time to
> hunt the bug down ...)

> any ideas ?

I had the same problems as you did, also with a masqueraded local network
and a Teles 16.3 ISDN-card.(also tried several kernel-versions and
For some reasons however I had set (a long time ago) the MTU for the eth0
at 1500 on my masqueraded hosts and for the ippp0 on the gateway at 576
After changing the eth0 MTU-size on all my masqueraded hosts also at 576,
the problem went away....
Don't now the technical details about it, but I can imagine that a sort
of overflow will occur when you try to transmit packages with a size of
1500, and the gateway have to resize the packages to 576

Ruud van Hemert