Have Securemote VPN-1 client version 4.1 SP-5 DES build 4199 running
on Win 2000.  Connects to an office LAN email server just fine
anywhere but on my home network.  Home network has Linksys 4-port
wireless router.  I'm no networking expert, but asked the office
'help' desk and they gave me some UDP and TCP ports to forward, but
this doesn't seem to work.  I'm not NAT'd through my ISP, I've got a
fixed IP.  I'm happy to go through trouble-shooting on this to
diagnose and provide more information.  My router has the most recent
firmware patch.

On Linksys routers, there is a setting called "VPN Passthrough" that
must be enabled for this functionality.

Don't know if this will help but...

I recently purchased Linksys WRT54G (wireless broadband router) which
allowed vpn passthrough with Securemote NG FP3 (build 53515) when
connected to one of the four network ports. Very minimal set up
required on the router (no port malarky).

However, when connecting wireless - no joy whatsoever using VPN
(although web browser etc was OK). Secureremote was not binding my
wireless adapter.

Resolved by uninstalling Securemote completely from notebook and
re-installing. Worked first time!