Github无法push

1. Test availability first

   $ ssh -T -p 443 git@ssh.github.com

   Note:

   Why we need to use this command to test?

   It's useful when:

   • Standard port 22 is blocked by a firewall or ISP
   • You're on a restricted network (corporate, school, public Wi-Fi)

   Port 443 (HTTPS) is almost always allowed, so using SSH over this port bypasses restrictions while keeping the security of SSH.

2. Edit vim ~/.ssh/config

   Host github.com
     Hostname ssh.github.com
     Port 443
     User git

3. Then test again:

   ssh -T -p 443 git@ssh.github.com

   you will see : Hi ... ! You've successfully authenticated.