NETGEAR (LG2200D) - page 40

Control Access to the Internet
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U.S. Cellular® 4G LTE™ Router (LG2200D)
5. The IRC server sends a return message to your router using the NAT-assigned source port
(for example, port 33333) as the destination port. The IRC server also sends an “identify”
message to your router with destination port 113.
6. When your router receives the incoming message to destination port 33333, it checks its
session table to see if a session is active for port number 33333. Finding an active session,
the router restores the original address information replaced by NAT and sends this reply
message to your computer.
7. When your router receives the incoming message to destination port 113, it checks its
session table and finds an active session for port 113 associated with your computer. The
router replaces the message’s destination IP address with your computer’s IP address and
forwards the message to your computer.
8. When you finish your chat session, your router eventually senses a period of inactivity in the
communications. The router then removes the session information from its session table,
and incoming traffic is no longer accepted on port numbers 33333 or 113.