A routing mystery

Steve Grandi (grandi@noao.arizona.edu)
Wed, 2 Sep 87 14:06:05 MST

I have a mystery I don't understand; perhaps someone out there with more
knowledge can enlighten me.

My building Ethernet is network 192.31.165 (noao-tucson). One VAX 11/750,
noao.arizona.edu, running 4.3BSD serves as gateway between my net and the
University of Arizona net (univ-ariz, 128.196). A gateway machine on
univ-ariz, jvax.ccit.arizona.edu is linked to the Princeton Supercomputer
center (jvnc-net, 128.121.0) where a gateway machine, fuzz.csc.org,
connects to the NSFnet. Hosts on noao-tucson have default routes to
noao.arizona.edu which has a default route to jvax.ccit.arizona.edu which
has a default route to fuzz.csc.org.

noao.arizona.edu serves as a central TCP/IP mail machine for our facility;
thus I spend a lot of time watching mail queues. What I see is an almost
total inability to communicate to wiscvm.wisc.edu, the Bitnet mail gateway
(at least for a couple more months). Since the other astronomers here beat
on me to get the Bitnet mail flowing, I've been poking around and have
discovered the mystery.

>From noao.arizona.edu ( and, pings and telnet
attempts to wiscvm.wisc.edu fail. Yet, simultaneously, pings and telnet
connections from aquila.noao.arizona.edu ( to wiscvm work
fine, even though the packets from aquila have to go through
noao.arizona.edu to reach wiscvm! Similar attempts from
jvax.ccit.arizona.edu to contact wiscvm also fail.

The only explanation I can come up with is that there is bad routing
information somewhere in the Internet for net 128.196, but good routing
information for net 192.31.165. How can I investigate this possibility?
Or am I missing something obvious?

Steve Grandi, National Optical Astronomy Observatories, Tucson AZ, 602-325-9228
UUCP: {arizona,decvax,hao,ihnp4}!noao!grandi or uunet!noao.arizona.edu!grandi
Internet: grandi@noao.arizona.edu SPAN/HEPNET: 5356::GRANDI or DRACO::GRANDI

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