OpenSUSE Network :: High Capacity Scalable Server - How To Overcome Limitation

I am writing some server programs. I notice that I can only connect to the server with a total of 28232 connections (clients) before I get the errno [99] "Cannot assign requested address" from the client program. I am using the same machine to do both operations. It seems like I am reaching some networking limitation outside of both programs.The server process has a maximum of 6 theads running(well below the thead limit). The client has two threads. When I add another client machine to the testing I can surpass 28232 connections). What limitation am I reaching on the server machine and how can I overcome this limitation. Again when I add a client machine to the testing, I can achieve more than 28232.

System Setup:
SUSE 11.1 64 bits
ulimit nofile=150000