On the server, put this snippet in ~/.bashrc to automatically open tmux on ssh
# Open Tmux Session immediately on SSH and exit SSH Session when exiting tmux
if [[ -n "$PS1" ]] && [[ -z "$TMUX" ]] && [[ -n "$SSH_CONNECTION" ]]; then
tmux attach-session -t ssh_tmux || tmux new-session -s ssh_tmux;
exit;
fi