Subject: DVMRP route filtering

From: Christian Isnard - CERN/IT/CS/EN <[email-masked]>
Date: Fri, 7 Feb 1997 17:22:44 +0100 (MET)

We run an MBone tunnel between an mrouted v3.8 and a CISCO router:

     +---------+                       +-------+
     | SUN     |      Tunnel           | cisco |-----
     | mrouted |=======================| PIM   |-----
     |         |                       |       |-----
     +---------+                       +-------+
    192.65.185.20           128.141.211.6     137.138.0.0

Everything seems fine. However after upgrading the cisco to IOS Version 11.1(9)
the cisco log fills up with the following messages:
...
Feb  5 12:17:44 b513-b-rci47-1-mb1 28: Feb  5 12:17:43 MET: %DVMRP-1-ROUTEFILTER:
 DVMRP route 137.138.0.0/16 from 192.65.185.20 discarded
Feb  5 12:18:45 b513-b-rci47-1-mb1 29: Feb  5 12:18:44 MET: %DVMRP-1-ROUTEFILTER:
 DVMRP route 137.138.0.0/16 from 192.65.185.20 discarded
Feb  5 12:19:46 b513-b-rci47-1-mb1 30: Feb  5 12:19:45 MET: %DVMRP-1-ROUTEFILTER:
 DVMRP route 137.138.0.0/16 from 192.65.185.20 discarded
...

Is there a way of preventing the mrouted from announcing DVMRP route
137.138.0.0/16 ?

Thanks in advance,
--
Christian Isnard - CERN - IT/CS

---

From: Bill Fenner <[email-masked]>
Date: Fri, 7 Feb 1997 14:20:12 PST

>Is there a way of preventing the mrouted from announcing DVMRP route

Could you kill -USR1 `cat /etc/mrouted.pid`, and post the header with
the vif/neighbor information and the line for the route 137.138.0.0/16
from the /usr/tmp/mrouted.dump that gets created?  Given your drawing,
the only way the mrouted should be advertising 137.138.0.0/16 is via a
poison-reverse, and it doesn't make sense to filter poison-reverses.
If we look at the mrouted.dump perhaps we can see if there's something
else going on.

  Bill