Unable to Connect to GitHub.com For Cloning

You can make git replace the protocol for you

git config --global url."https://".insteadOf git://

See more at SO Bower install using only https?

Open port 9418 on your firewall - it's a custom port that Git uses to communicate on and it's often not open on a corporate or private firewall.

I had the same error because I was using proxy. As the answer is given but in case you are using proxy then please set your proxy first using these commands:

git config --global http.proxy http://proxy_username:proxy_password@proxy_ip:port
git config --global https.proxy https://proxy_username:proxy_password@proxy_ip:port

You are probably behind a firewall. Try cloning via https – that has a higher chance of not being blocked:

git clone https://github.com/angular/angular-phonecat.git