Cannot ping REAL server IP addresses from CSM 6500

[r.catallo]

I have a dual 6500/CSM routed topology in which the traffic from clients to the server VIP works fine. However, in preparation for some upcoming work, I find that I cannot ping the REAL server IP addresses. This would seem to be an important troubleshooting step. Any ideas why this wouldn't work?

[Gilles Dufour · Accepted solution]

in routing mode, the CSM blocks by default traffic going directly to reals.

You can permit this traffic by catching it in a vserver.

Assume your servers are in subnet 10.10.10.0/24, you would do something like this

serverfarm route

predictor forward

no nat server

!

vserver real_access

virtual 10.10.10.0 /24 any

serverfarm route

inservice

!

Gilles.

[r.catallo]

Thanks Gilles for your quick response.

Ron Catallo

NPC

[r.catallo]

Gilles, followup question. If I understand this, what you outlined above will allow traffic external coming into the 6500/CSM to be forwarded thru to the REAL server IPs. If it wasn't clear, I was trying to ping from the native-mode 6500 that contains the CSM. I've tried regular and extended pings using the CSM-configured server VLAN's IP and alias IP, but get no response back from any of the REAL server IP addresses.

Is what you've indicated required to ping even if I'm on the 6500 which contains the CSM?

[Gilles Dufour]

The MSFC and the CSM use the same chassis but they are not a single device. The CSM considers the MSFC as an external device like any device you would attach to the catalyst.

So, yes, you need to use the configuration I gave you.

If you want to ping directly, you can ping from the CSM by dong 'ping mod csm X x.x.x.x'.

This will issue a ping from the CSM and does not require any particular config.

Gilles.

[r.catallo]

This works great! Thanks again for your help.