Originally Posted by Link

Quakenet may not be letting you connect without an ident because they have had problems with abuse from your address or ISP. Idents allow multiple users from the same address to be uniquely identified by username, so bans can be more specific.

If you're using a router or gateway, you will have to forward port 113 to your computer. This process varies depending on your configuration. Also ensure that it is not being blocked by any firewalls.