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CSM in bridged mode with MSFC

Hi we got a MSFC and a CSM module on Cisco 6513 switch. Csm is in bridged mode. The problem is we can reach the servers behind CSM with no problem. But we can not ping any of the VLAN interfaces on the MSFC from the servers . What might be the problem ?

7 REPLIES
New Member

Re: CSM in bridged mode with MSFC

Dumli,

The problem may be that both the CSM client and server vlans are configured in the MSFC. When using a CSM, only the client or the server vlans can be configured in the MSFC, but not both. If both are configured, the MSFC will route traffic rather than passing it through the CSM.

The first test you should try is to ping the CSM server vlan address from the reals. Ensure that the default gateway configured in the reals is the MSFC ip address for the CSM's client vlan, which should also be pingable from the reals.

The CSM only functions correctly with a single "gateway" configured. In CSM bridge mode, you do not require any gateway configured, so if you have multiple then you should remove them all, then test again.

Regards, Peter

New Member

Re: CSM in bridged mode with MSFC

Hi,

You are definitely right. I removed the line

interface vlan 43

no ip address

on the msfc. Still can not ping the other vlan interfaces on msfc. I can ping the virtual IP on CSM and also other servers behind the csm.

New Member

Re: CSM in bridged mode with MSFC

We removed the vlan 43 and 143 from PFC and MSFC. Then reconfigured all the vlans on both MSFC and CSM. It worked ok. Thanks for your help.

New Member

Re: CSM in bridged mode with MSFC

Dumlu,

Try pinging MSFC interfaces or to networks beyond the MSFC for your testing, rather than the CSM interfaces. When using multiple client and server vlans on the CSM, problems such as this are not uncommon, but frequently the routing is actually working fine beyond the CSM.

If the CSM is the cause, you will see "Drops vs/vlan" in the output of "show module csm tech all", indicating that the CSM is trying to route, then dropping the packets because the ingress+egress ports for the ping and response do not match. Often removing all route and gateway statements from the CSM config can resolve this.

Regards, Peter

New Member

Re: CSM in bridged mode with MSFC

Hi again,

Strange things going on again. We tried to move vlan 143 behing FWSM module and we are started having problems again. And even the case engineers couldnt find a solution to this. We can ping some of the servers from behind the msfc and we can NOT ping some of them from the FWSM. Im attaching all the sh tech outputs. If someone can figure this out Ill really appreciate it.

Cisco Employee

Re: CSM in bridged mode with MSFC

you will have to sniff the traffic in all vlan involved and see what is going on.

If it works for some servers and not others, the config is probably good but there is sth special about the servers.

Did you try to clear the arp cache on all the devices ?

Gilles.

New Member

Re: CSM in bridged mode with MSFC

Hi,

Yes actually, we cleared all arp caches on all servers modules and 6513. Didnt solve the problem. Then we decided to go with the routed mode. But now we need to do a configuration that

1_ allows the servers, initiating connections to client side and

2_ also we need clients to access the real server IPs

There is an example for the second thing on the documents but we couldnt make it work either.

but for the first we couldnt find any ex.

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