CEF and IPSec

[phaering]

I am trying to introduce a new Cisco 7120 into my VPN configuration (older device has failed). My new device is not allowing my IPSec traffic to connect. The only difference in the configurations between the two devices is that one had a default setting that enable CEF on the new device. Is there any known conflict between CEF and IPSec on the series 7100 Cisco routers?

[k.poplitz]

There might be arp cache issues on your surrounding routers and any directly connected devices.

[cjacinto]

On some codes, cef and IPSec would not coexist. Otherwise it should be able to work together. Normally the problem with cef and IPSec is that it builds the tunnel but not pass traffic. If you are not establishing the tunnel at all, it could be a different issue altogether.