I can’t believe Apple didn’t fix the biggest flaw of iChat in Leopard — you just can’t go through with this message popping up every single time,

Apple support forums are full of people reporting the problem since iChat have been introduced, in 2003. From what I understand, iChat use the SIP protocol to initial the video chat. Unfortunately it doesn’t always play fair with NAT routers and firewalls.

iChat is supposed to work with UPnP routers that would open ports on-demand so that you don’t have to do it manually.

But the strangest thing about it, is that it works sometimes without changing anything to my network or the one of the person I’d like to reach. I suspect some ISP to block the SIP traffic for unknown reasons.

What I don’t understand though, is why Apple didn’t drop SIP in favor of a proprietary technique, nobody really cares about how iChat does it job as long as it works out of the box.

Skype works everywhere, anytime.