Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!decwrl!labrea!aurora!eos!ames!pasteur!ucbvax!TAURUS.BITNET!leonid
From: leonid@TAURUS.BITNET
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Exchanging serial numbers
Message-ID: <669@taurus.BITNET>
Date: 28 Feb 88 11:56:22 GMT
References: <8802251906.AA04676@wb6rqn.UUCP>
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: virgo!leonid (Leonid Rosenboim)
Organization: Tel-Aviv Univesity Math and CS school, Israel
Lines: 23

In article <8802251906.AA04676@wb6rqn.UUCP> brian@wb6rqn.UUCP writes:
>Here at Sirius Systems we have been discussing a means to protect our
>TCP/IP software without placing undue strain on the users. ...

May I mention a very much similar solution done by Sun Microsystems in their
PS-NFS 2.0 product, and please excuse me if this has already been mentioned.
They just used ICMP discard packets to broadcast the serial number of each
booting system. All non-PC-NFS system dropped those packets as they should,
while all PC-NFS's look at this broadcast, make some sanity check and compare
it to their own. If a violation has been detcted, the punishment is to
stop both systems with the same number and print an appropriate message
to the screen.

To tell you the truth, I'm not really sure weather they use ICMP discard or
UDP discard packets, but all are better than try to twist TCP for one's
particular needs. Also, if a serial number problem would cause a TCP connection
to fail, how a user would know that there is a problem hah?

It seems that some vendors that really need a serial number protection scheme,
should try to define a new UDP service which would very conveniently handle
this and maybe other problems.

Leonid