ESP packets get dropped by Cisco 765 M ISDN routers?

[dan.olsen]

Hi,

I'm testing a VPN product through a Cisco 765 M ISDN (c760-i.b.NET3 4.3(1)) router configured with ip pat. The key exchange (using UDP) works like a charm but when trying to communicate through the tunnel (i.e. sending ESP packets through the router), nothing happens. After some checking it seems like the router just drops the ESP packets (since they're not UDP, TCP or ICMP packets). Is this true? Or might the problem be somewhere else?

TIA,

Dan Sveen Olsen

[s-doyle]

Yes this is true. The router will drop the packets. You cannot do IPSEC over PAT unless you are using a 3000 series concentrator which supports NAT transparency.