[Openswan Users] IPSEC/L2TP Server behind a Firefall with NAT

[foren titze]

Hello,

Now, I have a woking IPSEC server with an public IP. The server is behind a 
firewall with forwarded ports 4500, 500 and esp 50. the server runs debian 
with openswan 1.0.8, kernel 2.4.29-grsec.

In the next days we want make a new firewall. then all public IPs are to be 
nat'd in the firewall. 
So the server will get an internal IP and will be nat'd. 
What I have to change, except the ip's in ipsec.conf?
The clients will be always behind a nat-fireall like DSL


thanks