NETGEAR CG814WG V2, Справочное руководство

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Reference Manual for the Wireless Cable Modem Gateway CG814WG v2
Protecting Your Network 5-9
If the service you would like to forward is not in the predefined list, you can add a custom
service. Enter the range of ports you would like to forward and select whether the ports are
TCP, UDP or Both.
2. Enter the IP address of the computer on your network to which you would like to direct the
inbound traffic
3. Click Add.
4. To access the local computer from the Internet, you must use the WAN address of your
gateway, which can be found on the Basic Settings page.
• To delete an existing rule, select its button on the left side of the table and click Delete.
Using Port Triggering
Port Triggering is an advanced feature that allows you to dynamically open inbound ports based on
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 in incoming port
temporarily and can 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.
An example of Port Triggering for Internet Relay Chat (IRC) is shown in Figure 5-7 . When you
connect to an IRC server, the server tries to connect back on port 113 to do an Ident lookup. Unless
you have configured Port Forwarding to open port 113, the traffic will be blocked. In this example,
the initial login to the server in the range of ports 6660 to 6670 will be detected. This will trigger
the gateway to temporarily forward port 113 to the PC that initiated the login.