Re: 2.1.99 sends ULTRIX death packets

David S. Miller (
Fri, 1 May 1998 08:33:22 -0700

Date: Fri, 1 May 1998 17:30:27 +0200
From: Pavel Machek <>

we want to know what linux's feature does it (so we have nice post
to bugtraq) and

we do not want to be *that* evil.

We do want to be that evil if the bug is what I think it is, that
Ultrix crashes when it encounters unknown TCP options, such as the
rfc1323 and SACK stuff we implement these days.

The one thing which can stop wide deployment of these necessary
features is biting the bullet and by default disabling them, I refuse
to do that in Linux 2.2's TCP.

The answer (again this is assuming that Ultrix is puking on the TCP
option additions we have now, it may well not) is to leave it on by
default, and tell people who have this problem to turn it off on their
Linux machines via the sysctl mechanism. This will make everyone

We maybe should give Ultrix _some_ chance to fix bug before linuxes
2.1.99+ will be so common that their machines will be more down
than up.

Is Ultrix even maintained these days? Just curious...

In any event I'm looking forward to tcpdump output from people who see
this, so we can nail down what is happening.

David S. Miller

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