Ok, the only way I've connected up via VPN is direct into my server, from my home network. I've just used the standard windows setup software, nothing extra. Don't have a router/firewall at the office - the firewall is software as part of the server SBS2000 (which runs over the top of Win"K server).
Lots of questions, but perhaps no answers, but may give someone more clues as to where to look:
You say you can make a connection, presumably you get messages that it has all authenticated OK?
The user name you are accessing the office network on has full remote access rights?
Is the server fully patched?
If you are authenticated, does an IPConfig/All command (using the dos command prompt) give any odd messages?
Can you ping any part of the network by specific IP address, or even the computer names, when you are authenticated.
Does anything happen if at your windows Run command you type the line "
\\servername" ?
Do you have any software firewall running on your local PC or the server, as well as on the 3-com things?
Presumably you have followed 3-com's guidance as to how to set up their the firewall router things to speak to each other over VPN?