troubleshooting return traffic with 1841+vpn client
On 15-Dec-2005 I posted a message entitled "some return traffic not going through vpn tunnel (although not all)". Either the post was overwhelming or considered not worthy of a reply so I will attempt to simplify it in the hopes of getting some feedback.
Basically I am trying to determine why port 25 TCP traffic flows correctly (through the VPN tunnel) from the VPN software client to the SMTP server behind an 1841. However, return traffic from the server to the client does not flow back through the VPN tunnel (it routes back out through the public IP address). Traffic on other ports seems to flow properly back and forth in the tunnel.
It seems like the SMTP server does not know how to route the traffic back through the tunnel to the VPN client so it sends the packets out the default gateway. There are no static routes other than the entry for default outbound traffic:
ip route 0.0.0.0 0.0.0.0 Dialer0
Port mapping and other NAT entries are as follows:
ip nat inside source list 110 interface dialer0 overload
ip nat inside source static tcp 10.0.0.209 25 interface dialer0 25 ! exchange smtp virtual server
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...