Is there a difference regarding the network environment between the Win/Ubuntu combination. I.e. is there a firewall in between?
Could you try the same if you use the Win client and connect to the AIX server?
There is no firewall between. Every time when my client app crashes i got one more CLOSE_WAIT connection on server side. I also tried win/aix combination with no success. Also, port 9990 for remote managment doesn't work either. I have a lot of CLOSE_WAIT connections on that port also. JBoss on AIX is bundled with liferay.
What does it mean if you say "Every time when my client app crashes"?
Maybe it is a JDK problem, could you try the last Java 1.6 or is it possible to check with Java1.7?
I don't think it is a JBoss issue but you might try the latest nightly build.