Problems connecting to work VPN through ADSL Router

Archived from groups: comp.dcom.vpn (More info?)

Hi, hope someone can help

I access my office network through VPN using Checkpoint SecureClient VPN-1.
My ADSL router is a SAFECOM SAMR-4114.

Ok, I get authenticated ok but when I try to do things like browse network
and open email it times out and Secureclient reports Virtual Defragmentation
Errors. I'm gathering this is an MTU issue. I tried lowering the MTU on
the router to 1300 (and lower) and I still get the same problem, it would
appear the packets being dropped are inbound rather than outbound, I've used
DrTCP to reduce MTU on my connnections, but I'm wondering if something needs
to be done server-end.

SC also says "MTU Tunnel set at 1292 (probably black-hole)". I also noticed
that the max MTU setting on SC is 1350 (too high for my adsl I think).

Any ideas??
Thanks
Desperate Kev