topic TCP Sequence numbers in Operating System - HP-UX

TCP Sequence numbers

Kent Kaiser — Mon, 08 May 2000 13:50:33 GMT

I recently used Nessus to scan our network and one error said the TCP sequence numbers were always incremented by 6400 and would be easily guessed. I havn't been able to find a patch on the HP web site. Is there a fix for this?

Thanks,
kent

Re: TCP Sequence numbers

Dan_4 — Mon, 08 May 2000 22:54:23 GMT

You should probably move this discussion to the networking forum :)

Re: TCP Sequence numbers

Ralf Hildebrandt — Wed, 02 Aug 2000 08:24:44 GMT

There's an easy solution.
my script /sbin/init.d/hack_ip_stack does that.
Invoke using
/sbin/init.d/hack_ip_stack start

Re: TCP Sequence numbers

John Palmer — Wed, 02 Aug 2000 08:34:48 GMT

For HP-UX 10.20:-

nettune -s tcp_random_seq 1
will randomise the initial connection sequence.

nettune -s tcp_random_seq 2
uses a 'more sophisticated' randomiser.

The default is 0 (normal as per RFC 793).

Note that randomising is on by default for HP-UX 10.30 and later.

Regards,

John

Re: TCP Sequence numbers

Berlene Herren — Wed, 02 Aug 2000 11:43:51 GMT

Excellent answer, John!

berlene