Port forwarding
Port forwarding is a rule configured on a router or firewall that takes inbound traffic arriving on a specific port of the public IP address and forwards it to a chosen device and port on the local network. It is how a game server, security camera, or self-hosted web app behind a home or office router can accept connections initiated from the internet, since without it the router's NAT would simply drop unsolicited inbound packets. The tradeoff is that whatever is listening on the forwarded port becomes directly reachable by anyone on the internet, not just intended users, so an outdated or misconfigured service behind a forwarded port is a common way home and small-office devices end up exposed. Universal Plug and Play (UPnP) lets applications request forwarding rules automatically, which is convenient but removes the manual review step that catches unnecessary exposure.
By AdminKit team, Netbase JSC · Updated