Charles M. Hannum said:
> A user sent me the following tcpdump output, regarding a problem where
> a connection between a machine running HP-UX (hp.rc.vix.com) and
> NetBSD (xenon.rc.vix.com) would `freeze.'
> It appears that the HP box is resetting its time stamp. (Note that
> the time stamp on the 00:19:25.226717 packet is `less than' the time
> stamp on the 00:18:05.615634 packet.) This causes the PAWS check to
> fail on all future packets, and they are therefore dropped by the
> NetBSD box after sending an ACK.
Yes, your user has hit an old bug that was fixed quite a while ago.
> This would seem to be a bug in the HP-UX implementation of RFC 1323.
> It looks to me like HP-UX is using a 16-bit counter and updating it
> every .01s, whereas NetBSD is using a 32-bit counter and updating it
> every .5s. The granularity isn't really an issue, but it seems to me
> that rolling over at 16 bits is clearly wrong.
> For reference, the version of HP-UX in question is:
> HP-UX hpd280 B.11.00 A 9000/820 2006777451 two-user license
> Could someone verify that I'm not on drugs here?
I'll just say that your interpretation of the tcpdump output is correct. I'll
also say that this problem was fixed shortly after HP-UX 11.0 was released,
so your customer should probably grab and install the appropriate patch
(the latest cumulative patch is PHNE_16645).