Debian stable can't connect to port 443

I am having a strange problem and don't know where to start looking. This is a Debian stable server box, no GUI. I am unable to connect to port 443 on other machines when trying it from the box in question.

I realized the problem when i started to clone something from git. The connection just timed out. Afterwards I tried to use wget to get the download from a different source. Same problem. Even telnet anyhost 443 just times out.

I can connect to port 80 and 25 just fine. No iptables on the machine. Other servers in the same subnet which use the same gateway can connect to external hosts on 443 just fine.

I really have no idea what might be wrong.