Subject: Re: tcp_do_rfc1323 vs Linux - any solid understanding?
To: Ken Hornstein <>
From: Peter Galbavy <>
List: current-users
Date: 06/10/1996 07:33:27
> This _has_ been discussed before, honest :-)

And still not fixed.

> The reasons that the IP options used in RFC 1323 cause problems are generally
> twofold:
> - Some boxes have "less than optimal" IP implementations, and just can't
>   deal with them.  For example, some older Annexes would crash upon getting
>   packets with IP options set.
> - IP options interact badly with some versions of PPP when VJ header
>   compression is enabled.  For example, Telebit Netblazers will eat packets
>   that have IP options set if you use PPP and VJ header compression.

and three

  - The rfc1323 implementation in NetBSD is "sub-optimal".

The problems generally apply two fold when you have two NetBSD systems. One
NetBSD and one (for example) Solaris system are nowhere near as bad in
performance terms (i have no recorded benchmarks... yet) as two NetBSD

> I would try two things:
> - Turn off VJ header compression on the PPP connection
> - Turn off rfc1323 via sysctl.
> There's really nothing else you can do (other than fix the bugs in the other
> systems :-) ).

If I knew enough about how and why then I might, but all I do is turn it
off in netstart on every new install. This *should* be the default.

The danger in leaving it on (or not fixing it), is that new users
will see appalling network performance between two NetBSD systems
and go back to using Linux. :( Or whatever. Any chance we can have
this wonderful "feature" off by default for 1.2 ?

Does anyone have a good word to say about our rfc1323 support ? Apart from
the standards confirming bit.

Peter Galbavy                                 
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in Wonderland