It only opens up to another machine validated by public keys.
It serves similar purpose as opening firewall to just a specific IP/port and dynamically change the IP/port as the other machine moves or disconnects. One of the main advantage is that it works behind NATs you don't control (i.e. public WiFi).
Edit: also most home routers do not have the ability to dynamically open up to specific IPs based on where your outside machine is.
It serves similar purpose as opening firewall to just a specific IP/port and dynamically change the IP/port as the other machine moves or disconnects. One of the main advantage is that it works behind NATs you don't control (i.e. public WiFi).
Edit: also most home routers do not have the ability to dynamically open up to specific IPs based on where your outside machine is.