Recently there is a very annoying setting within debian squeeze. It causes many java applications to not function anymore on ipv4. Basically this means a lot of programs like Eclipse and Netbeans won’t function at all when requiring a connection.

This can be fixed by editing the following file:
/etc/sysctl.d/bindv6only.con

You should see the follow setting:
net.ipv6.bindv6only = 1
change this to:
net.ipv6.bindv6only = 0

Restart your system and your apps should be functioning properly again.

It took me several hours to find this solution, so I hope posting another article helps other people in search of a solution.

Thanks for reading.