Port Forwarding
In plain terms
Redirecting traffic from one address/port to another.
Going deeper
Port forwarding routes external requests on a specific port to an internal device, exposing services behind NAT. It opens a path inward.
Under the hood
Configured on routers/firewalls; needed to reach internal servers from outside, with security implications.
Examples
Hosting game/web servers at home, NAT traversal, remote access, SSH tunnels.
Think of it like...
Like the front desk forwarding all calls on extension 80 to a specific back office.