Port forwarding is a process used to allow external devices to connect to your local network. If your Linksys router's port forwarding feature is not working, it may be due to a number of reasons such as incorrect port forwarding settings, outdated firmware, or a firewall issue. To resolve this, you can try resetting your router to its default settings, updating the firmware, or configuring your firewall settings. If the problem persists, you may need to contact Linksys customer support for further assistance.