Eboard does not work behind natted networks like fastweb.
It's weird because other network applications like instant messaging, web, p2p, irc, ssh, mail, and so on works.
do you mean for FICS connection or for peer-to-peer play with another eboard ?
Connection to FICS requires a TCP connection to freechess.org port 5000, you can try it with "telnet freechess.org 5000". NAT is not an issue (but firewalls blocking outgoing connections to port 5000 are).
FICS accepts connections to port 23 too. It is only a reportable eboard bug if you can do the telnet but can't connect with eboard or other interface (such as xboard).
Receiving an incoming connection for a peer-to-peer game over NAT is not technically possible.
i mean a connection to FICS server from my eboard.
I already tried with telnet and it works.
If you need further information ask...