Set higher CompressionLevel than defaut for my home slow/costly inet.
# Allow sharing of multiple sessions over a single network connection for all
# host. Also don't prompt for password when connection live.
Host *
ControlPath ~/.ssh/sock_%r@%h_%p
ControlMaster auto
# This by default.
# UserKnownHostsFile ~/.ssh/known_hosts
# Enable compression. To turn on it manually invoke ssh with -C key.
Compression yes
# CompressionLevel has value 1..9 (fast..slow/best) with default 6.
# Applicable for SSH protocol version 1.
CompressionLevel 8
# Prefer public key authentication.
PreferredAuthentications publickey,keyboard-interactive,password
PubkeyAuthentication yes