Answer Description

The outbound port should be blocked to ensure no one can connect to the webcam outside of the LAN. This is probably the default setting for the router, but you should still check to be sure.

Wikipedia

In computing, a firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted network and an untrusted network, such as the Internet.