Forums Connection Issues Unable to connect to server (Connection timed out)

I'm receiving this message each time then I'm trying to connect to irc.omnitel.net . I'm using 6667 port. That happen about 2 week ago. I'm using Mirck v6.16. I have tried to use other programes but the result was the same. I'm able to connect only through this web site: http://nilix.net/cgi-bin/chat/irc.cgi
Please help me.

Edirola

Are you using a firewall.. or behind router?

I do not use firewall. My computer belongs to the LAN which is conected to the internet throught the ADSL modem.

LAN == generally has a NAT firewall
ADSL modem == generally has a NAT firewall
Windows XP == has it's own firewall (if you have XP)