Reverse-ssh.service

• Forward local port 22 to remote server port 5000
• Server is host.org with ssh port 1022

[Unit]
Description=AutoSSH tunnel service for ssh                               
After=network.target

[Service]
Environment="AUTOSSH_GATETIME=0"
ExecStart=/usr/bin/autossh -M 0 -o "ServerAliveInterval 30" -o "ServerAliveCountMax 3" -N -R 5000:localhost:22 devnull@host.org -p 1022

[Install]
WantedBy=multi-user.target