Host * !github.com
  Port 516
Host abc
  Port 2222
Match host xyz canonical
  Port 2223

Host *
  ForwardAgent no
  Compression no
  ServerAliveInterval 0
  ServerAliveCountMax 3
  HashKnownHosts no
  UserKnownHostsFile ~/.ssh/known_hosts
  ControlMaster no
  ControlPath ~/.ssh/master-%r@%n:%p
  ControlPersist no