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New Member

CSM : traffic originated by server side

Hi all,

a simple question : in a CSM environment configured in router mode with multiple vlan server and client, is possible to force traffic generated by a server on a particular server lan and destined to an external server ( not under CSM ) to exit through a particular client vlan?

Because each vlan client has a default gateway, now the traffic generated by the server use not always the same gateway.


Cisco Employee

Re: CSM : traffic originated by server side

you can configure as many gateway that you want, the CSM only uses one. The first gateway to respond to arp request.

So, an easy solution is to configure only 1 gateway.

If you want multiple vlan, you can create a vserver to catch your server traffic, and use a serverfarm with your selected gateway configured as a real and 'no nat server'.


serverfarm gw1

no nat server

no nat client

real x.x.x.x


vserver server2server

vip x.x.x.x/x any

serverfarm gw1




New Member

Re: CSM : traffic originated by server side

Hi Gilles,

thanks for your explanation but I have a doubt due to my poor experience on CSM env :

from you example the real and vip adddress are the same ip address or not?

In our env ( Cat 6k , MSFC, csm module) each vlan client has only one default gateway equal to the corresponding ip address of msfc vlan interface, ie we have the msfc attached to client vlans.

Then the routing table of CSM have multiple default gateways and it choice one of these but statistically not always the same.One particular server, can accept sessions coming from external world trough the csm but have also to initiate session toward the external world.

Looking at the csm doc we also tried to use the direct server access config with predictor feature but we see that the default gateway change ( and then the client too), while we need to use always the same gateway (vlan client)

Thanks again