Application Example: Port Triggering For Internet Relay Chat [Router Mode] - NETGEAR WAX204 User Manual

WiFi 6 AX1800 Dual Band Wireless Access Point WAX204
Application example: Port triggering for Internet Relay Chat
[router mode]
Some application servers, such as FTP and IRC servers, send replies to multiple port
numbers. Using port triggering (if the access point is in router mode), you can tell the
access point to open more incoming ports when a particular outgoing port starts a
session.
An example is Internet Relay Chat (IRC). Your computer connects to an IRC server at
destination port 6667. The IRC server not only responds to your originating source port
but also sends an "identify" message to your computer on port 113. Using port triggering,
you can tell the access point, "When you initiate a session with destination port 6667,
you must also allow incoming traffic on port 113 to reach the originating computer."
The following sequence shows the effects of this port triggering rule:
1. You open an IRC client program to start a chat session on your computer.
2. Your IRC client composes a request message to an IRC server using a destination
port number of 6667, the standard port number for an IRC server process. Your
computer then sends this request message to your access point.
3. Your access point creates an entry in its internal session table describing this
communication session between your computer and the IRC server. Your access
point stores the original information, performs Network Address Translation (NAT)
on the source address and port, and sends this request message through the Internet
to the IRC server.
4. Noting your port triggering rule and observing the destination port number of 6667,
your access point creates another session entry to send any incoming port 113 traffic
to your computer.
5. The IRC server sends a return message to your access point using the NAT-assigned
source port (for example, port 33333) as the destination port and also sends an
"identify" message to your access point with destination port 113.
6. When your access point 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 access point restores the original address information replaced
by NAT and sends this reply message to your computer.
7. When your access point 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 access point 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 access point eventually senses a period of
inactivity in the communications. The access point then removes the session
information from its session table, and incoming traffic is no longer accepted on
port numbers 33333 or 113.
Port Forwarding and Port
Triggering [Router Mode]
220 User Manual