NETGEAR 108 MBPS WIRELESS WGT624 V3 - Manual (Page 54)

Reference Manual for the 108 Mbps Wireless Firewall Router WGT624 v3
6-4 Advanced Configuration
202-10090-02 v 1.4, July 2005
Some online games and videoconferencing applications are incompatible with NAT. The
WGT624 v3 wireless router is programmed to recognize some of these applications and to work
properly with them, but there are other applications that may not function well. In some cases, one
local PC can run the application properly if that PC’s IP address is entered as the default in the
PORTS Menu. If one local PC acts as a game or videoconferencing host, enter its IP address as the
default.
Using Port Triggering
Port Triggering is an advanced feature that allows you to dynamically open inbound ports on the
basis of outbound traffic on different ports. This is an advanced feature that can be used for gaming
and other Internet applications.
Port Forwarding can typically be used to enable similar functionality, but it is static and has some
limitations. Ports will be open to traffic from the Internet until the port forwarding rule is removed.
Additionally, port forwarding does not work well for some applications when your WAN IP
address is assigned by DHCP, and is changed frequently. Port Triggering opens an incoming port
temporarily and does not require the server on the Internet to track your IP address if it is changed.
Port Triggering monitors outbound traffic. When the gateway detects traffic on the specified
outbound port, it remembers the IP address of the computer that sent the data and “triggers” the
incoming port. Incoming traffic on the triggered port is then forwarded to the triggering computer.
Once configured, operation is as follows:
• A PC makes an outgoing connection using a port number defined in the Port Triggering table.
• This Router records this connection, opens the INCOMING port or ports associated with this
entry in the Port Triggering table, and associates them with the PC.
• The remote system receives the PCs request, and responds using a different port number.
• This Router matches the response to the previous request, and forwards the response to the PC.
• (Without Port Triggering, this response would be treated as a new connection request rather
than a response. As such, it would be handled in accordance with the Port Forwarding rules.)
Note: Only 1 PC can use a "Port Triggering" application at any time.
After a PC has finished using a "Port Triggering" application, there is a "Time-out" period before
the application can be used by another PC. This is required because this Router cannot be sure
when the application has terminated.