Logging on AppleShare IP server with DHCP IP number?


I've just bought a new iMac with MacOS X.
My Internet connection is Cable with a variable IP adress (DHCP)
I already had an AppleShare IP (6.3) server, in MacOS 9 I can always login on this server, but in MacOS X it's only possible when I manually enter an IP adress..
Does anyone know what to do?
I want an Internet and server connection!!

I hope my problem is clear..

Thanking in advance,

Mark Pith
The Netherlands