On Wednesday, 10/12/2005 at 10:42 CDT, Leslie Turriff 
<[EMAIL PROTECTED]> wrote:
> We are having a problem with our TCP/IP and MPROUTE service machines 
(running
> in z/VM 4.2 in two LPARs, CMSUVMA and CMSUVMB).
> 
> After some hosts in our local network moved to a new subnet they have 
become
> unreachable from the VM systems, and the routing information that would 
tell
> them where they are does not seem to be getting into the VM TCP/IP 
stacks.
> 
> TRACERTE shows that outbound requests are being routed back and forth 
through
> a CTC link between the two LPARs, and we can't seem to get past it to 
the proper
> outbound route.
> 
> I'm attaching the TCPIP and MPROUTE configuration files and the output 
from
> the NETSTAT GATE and TRACERTE commands.  I hope that someone out there 
can help
> with this strange problem.

You didn't attach a picture of your local network with subnet numbers and 
masks.  Bummer.  :-(  How else to know if you have the correct 
configuration?

One of the things I did notice is that none of the point-to-point links is 
defined in your MPROUTE CONFIG file.  Remember these MPROUTE Configuration 
Rules To Live By:
#1: Don't guess. If you do you will persecuted by your peers.
#2: If you don't code an interface definition, MPROUTE will discover it 
and use the defaults.
#3: Defaults are Evil.
#4: Dynamic routing and using the same IP address on the VM side of 
multiple p2p links gives unpredictable results.

You need an INTERFACE statement to describe your p2p links, and you you 
need to place each CTC link it its own subnet.  You can try a subnet mask 
in MPROUTE CONFIG of 255.255.255.255.  (Note that the direct route between 
the two systems is missing from NETSTAT GATE.)

WARNING: As of z/VM 5.2, this subnet mask trick won't work; a mask of 
255.255.255.255 is no longer permitted in MPROUTE.  Use Guest LANs and 
VSWITCHes where possible and allocate /30 (.252) subnets for remaining 
point-to-points.

Alan Altmark
z/VM Development
IBM Endicott

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