Airport Base Station renewing IPs after mapping ports

[hyperactive]

Okay I'm pulling my hair out here.
Basically I map an external port (e.g 4567) on the Airport to an internal machine IP/port (e.g. 10.x.x.9/4567 to allow external connections to my internal machine). Update and therefore restart the Airport. 1-2 hours l8r the airport decides to release and renew all internal machines ip addresses e.g 10.0.1.9 becomes 10.0.1.10. Thus making the port mapping useless. It is set to distribute DHCP n NAT automatically and the lease is set to 365 day expiry.
Any ideas plz?

 

[McDave]

I believe you must use 10.0.1.201 or higher (actually up to 10.0.1.254). These are the addresses that are outside the DHCP & NAT available range. Hope it works!

 

[PTmon]

On your client machine set your IP address manually. Don't have to use DHCP. It'll all be good
PT

http://mahon.homeip.net/remember