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 (128.196.4.1 and 192.31.165.2), pings and telnet
attempts to wiscvm.wisc.edu fail. Yet, simultaneously, pings and telnet
connections from aquila.noao.arizona.edu (192.31.165.6) 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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