ssh_config

Host example.com
  Port 22
  User qnighy
Host github.com
  CheckHostIP no
Host *
  # Share connections among processes
  ControlMaster auto
  ControlPath ~/.ssh/mux-%r@%h:%p
  ControlPersist 10

  # Agent forwarding: turn it off by default for safety
  ForwardAgent no

  # Keep-alive: prevent idle connection from being force-disconnected.
  # Server keep-alive is more robust against firewalls.
  TCPKeepAlive no
  ServerAliveInterval 15
  ServerAliveCountMax 3

  # Identity: use only known private keys
  GSSAPIAuthentication no
  PasswordAuthentication no
  PubkeyAuthentication yes
  # Ask not to use additional keys provided from agents and keyrings.
  IdentitiesOnly yes

  # Server auth
  # Fail if the IP address has been changed
  CheckHostIP yes
  # Store hostnames in cleartext for better maintenance
  HashKnownHosts no
  # Reject unknown host keys by default
  StrictHostKeyChecking yes
  UpdateHostKeys ask