Any errors on the MPROUTE console?  We've found that when things go bad, 
MPROUTE usually has a complaint.  You may want to turn on debug too.

Could both your MPROUTE and your zebra be advertising the same routes?   We 
inadvertantly did that with a /30 vipa subnet and it didn't matter until we 
moved some network connections around.


Marcy

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-----Original Message-----
From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf 
Of Martha McConaghy
Sent: Thursday, December 11, 2008 2:06 PM
To: IBMVM@LISTSERV.UARK.EDU
Subject: [IBMVM] Strange OSPF problem

This is a complicated problem, so please bear with the long preamble....

I have a VM TCPIP stack running level 520 on a z/VM 5.4.0 system.  It is 
connected to an OSA on one side and a guest lan on the other.  (It acts as a 
router for the guest lan.)  It uses OSPF, so I have a MPROUTE machine going 
too.  There is a bunch of stuff on the guest lan too, but they don't figure 
into this problem.  The OSA is shared with a Linux guest which acts as a 
firewall for a bunch of Linux servers on a guest lan.  So, here's the picture, 
1 OSA shared between 1 VM TCPIP stack and 1 Linux stack.  The Linux firewall is 
running zebra for dynamic routing.

All is good, everyone talks to everyone else, until I upgrade the VM TCPIP 
stack to level 540.  (Same config files.)  Both the TCPIP and MPROUTE machines 
come up fine.  NETSTAT GATE shows that the routes are there and everything 
looks OK.  The IP on the OSA side pings, no problem.  However, the IP on the 
guest lan side can't be seen by the network.  Pings fail.
Traceroutes go off into the ether.  To make things even weirder, the Linux 
firewall starts having the same problem.  All the Linux servers behind it 
suddenly disappear from the network as well.  At first, I thought this might be 
a VM TCPIP problem, but now I'm not sure.  Could this be affecting the routing 
tables in the OSA?  (Its an OSA Express1 Gbe on a z/990.)

I'm at a loss on this one.  As soon as I switch the VM stack back to 520 level, 
everything shows up again, including the Linux servers on the other guest lan.

Any ideas?  Am I doing something naughty?

Martha

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