Path: utzoo!mnetor!uunet!husc6!uwvax!dogie!uwmcsd1!ig!jade!ucbvax!sdcsvax!brian
From: brian@sdcsvax.UCSD.EDU (Brian Kantor)
Newsgroups: comp.protocols.tcp-ip
Subject: routing problems?  Core gateways?
Message-ID: <4481@sdcsvax.UCSD.EDU>
Date: 13 Jan 88 05:36:14 GMT
Organization: UCSD wombat breeding society
Lines: 45

I can't ping SEISMO.CSS.GOV from our host 'SDCSVAX.UCSD.EDU' at
26.5.0.3.  I can ping SEISMO quite nicely from our neighbor on the same
IMP (NOSC.MIL at 26.0.0.3).  We are both using the same default gateway
at 26.2.0.73, which seems to be the way the packets are going.

I guess that SEISMO could have different routes back to SDCSVAX than they 
do back to NOSC, but I don't know WHY they'd have them, since we're both
on the same IMP.

SEISMO isn't an isolated case - I can't ping any of the following hosts
from SDCSVAX, but I can from NOSC:

	uxe.cso.uiuc.edu	128.174.5.54
	mcc.com			10.3.0.62
	ius2.cs.cmu.edu		128.2.254.176
	cs.utah.edu		10.0.0.4

There are others.  And there are hundreds of mail messages waiting in
our queue because we can't get to their nameservers to get delivery 
addresses.  (There ARE hosts on network 10 that I can ping, btw, such 
as UCBVAX.)

I called the Milnet NOC, and they seemed to think that it's a core
gateway problem and told me to call BBN.  BBN assures me that they were
already working on the problem - seems that they see a problem with one
of the gateways, but I don't know what that problem would be.

I'd like to understand what's going on, as well as get it fixed.  The
only thing I can think of is that NOSC is connected to the IMP with
1822, and we're connected with X.25, but don't quite see how that would
make a difference either.  NOSC is running EGP for our 128.54 network, 
so I don't think that's the problem - if indeed that is even relevant,
since we're dealing directly with network 26 source addresses in the
pings.

Oh yeah, we've been having this sort of problem since Friday.  I'm not
sure it's always the same hosts.

I'm stumped.  Anybody got any ideas?  

	Brian Kantor
		UCSD Office of Academic Computing
		Academic Network Operations Group  
		UCSD B-028, La Jolla, CA 92093 USA
		brian@sdcsvax.ucsd.edu	(619) 534-6865