There is currently the situation that on some schools (and maybe also firms) in this region that only whitelisted ports to the outside world are opened. Connections are established through a socks proxy when you want to connect to a computer which is not part of the local network. They use simple pattern matching to find "dangerous" words before delivering the content to the client which of course creates many false positives. Most of time they disable encrypted versions of a protocol (like HTTPS or POP3S) so the users most use the unencrypted versions. The problem is that some content is only provided when you connect over https on some webpages (like login pages or svn commit support on sourceforge). "Unknown" ports will also be filtered - so git-fetch over git's own protocol will propably fail.

OpenSSH has some really nice unknown options which you find from time to time per accident. One of them is to share a connection between different sessions. It helps a lot when you are using multiple connections to a host or using zsh autocompletion over ssh and must wait until the connection was really established.