Your GitHub Enterprise installation may be behind some combination of firewalls and VPNs at your company. If you would like to access GitHub Enterprise from outside those security layers, you will need to open a few ports.

Specifically, you may need to allow the following connections:

Port Protocol Notes
22 SSH Used for Git over SSH and admin shell access
80 HTTP Only used when HTTPS/SSL is disabled
443 HTTPS Only used when HTTPS/SSL is enabled
9418 Git protocol Only used when private mode is disabled
13337 HTTP Used for remote access to the Management Console