Glassfish suddenly cannot be reached anymore remotely.

[Andre Sacramento]

sometimes it happens that our web application on our glassfish server (v2.1) suddenly cannot be reached anymore while on the server itself the web application still works.

After restarting the glassfish server all works normally again.

Port 80 is closed on the firewall. The application uses only https.

What could be the problem, how to proceed to detect it?

Environment:
Windows Sever 2003
2GB Ram
10-20 users

Sybase SQL Anywhere Database


Thanks a lot.