Concerning VPN and what ports to open

[ronnie.axelsson () systeam se]

Hi.

I've a small problem. I hava installed a firewall at a customer the   
resides on an regional net. This net does not have any "real" IP. The   
regional net is protected by a firewall and my question is: What ports   
must be open on the "external most" firewall?

This is what i look like:




Internet------------Firewall-------Regional   
net--------Firewall-----Lan----
                                                                        ^
                                                                        |
     This one is used for the VPN


I'm thankful for any tips

/Ronnie