SUMMARY: packet from unknown router

From: Ted Sasscer (esasscer@ppco.com)
Date: Thu Jan 19 1995 - 05:35:00 CST


Summary of answers to the following original Question:

> On a SparcStation 10, every 15 seconds I am getting a message:
>
> syslog: packet from unknown router, 172.21.83.249
>
> How do I convince Mr. Sun to recognize this router?
>
> Supporting evidence: We are changing from a Class C to a Class B address,
> with a Cisco router that supports secondary subnetting, which is turned on.
> The primary subnet is 138.32, and the secondary subnet is 172.21. I have
> stumped our known company Sun and network experts. Other non-Suns (RS/6000
> and SCO Unix PC) on this subnet appear to have no problem with this
arrangement.

Acknowledgements:

To those who responded, thank you very much. I received 6 answers, 1
me-too. David Deaves, from down under, gave the promptest and best
explanation, so I took his advice. Others basically said the same thing.

  David Deaves <David.Deaves@cbr.atr.com.au>
  Jorge Portugal Andrade <admin@di.uminho.pt>: Muito obrigado, senhor.
  grevemes@VTC.TACOM.Army.Mil (Steven Grevemeyer)
  "Malcolm C. Strickland" <chucks@orl.mmc.com>
  david@srv.PacBell.COM (David St. Pierre)
  matt@uts.EDU.AU (Jas (Matthew K))

Answer:

The problem is that 'routed' is getting a RIP packet telling it all this
good stuff about networks that can be reached via the gateway sending
the packet. All enthused 'routed' tries to add this info to it's tables
& then realises that It doesn't know how to reach the gateway.

Also be warned that AIX's default /etc/syslog.conf file basically
ignores most (if not all - ours is heavily modified & my memory is
disfunctional) messages. SCO on the other hand just puts it all in
/usr/adm/syslog (beware it may be huge by now).

Any how to a SOLUTION.

I expect that if you have a cisco router on your wire, you don't really
need 'routed' running on your machine, simply put an appropriate entry
in /etc/defaultroute (check the rc files for correct spelling) next
boot, 'routed' will not be started (thus no RIP errors) & the cisco will
be declared as the gateway. Also you can kill 'routed' & set a default
route yourself to avoid an immediate need to reboot.

Alternatively on some unixes including (SunOS 4.1.3) you can

        route add net 172.21.0.0 {your host name} 0

This however means that these routes via this address that you arn't
really may be added. Also try

        route add net 172.21.0.0 {your router name} 1

although I would have guessed that RIP should have added that already.

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