Timeout accesing a JBoss server with an application client

[dragospd]

I have a JBoss server installed on server side and an application client written in swing on the client side. The client access server using the internet. the timeout between client and server is about 300ms.
I cannot access the server with the application client because, after a few minutes application throws a timeout exception. Accesing the server on localhost or in a LAN is done without problems. What can cause this long delay? Does anybody encountered this problem?

thanks

[dragospd]

I forgot to mention that there are not firewals or other programs that could potentialy block the trafic between client and server. i can even telnet the server on 1099 port and the server responds immediate. Also i can see the jmx-console without any problem