Configuring the
Gateway
87
SMCD3GNV Wireless Cable Modem Gateway User Manual
Disabling Port Forwarding
To disable port forwarding:
1. If the Port Forwarding menu is not displayed, click
Advanced
in the menu bar, and then
click the
Port Forwarding
submenu.
2. Next to
Enable Port Forwarding
, click
Disabled
. The
ADD PORT FORWARD
button
becomes unavailable and all port forwarding rules that have been defined turn gray to
show they are disabled.
Enabling Port Forwarding
To enable port forwarding:
1. If the Port Forwarding menu is not displayed, click
Advanced
in the menu bar, and then
click the
Port Forwarding
submenu.
2. Next to
Enable Port Forwarding
, click
Enabled
. The
ADD PORT FORWARD
button turns
green, and all port forwarding rules that have been defined become available, along with
the
EDIT
and delete buttons.
Enabling or Disabling Port Triggering
Using the Port Triggering menu, you can configure the Gateway to detect port triggers for
detect multiple-session applications and allow them to pass the firewall. For special
applications, besides the initial communication session, there are multiple related sessions
created during the protocol communications. Normally, a normal treats the triggered
sessions as independent sessions and blocks them. However, the Gateway can co-relate
the triggered sessions with the initial session and group them together in the NAT session
table. As a result, you need only specify which protocol type and port number you want to
track, as well as some other related parameters. In this way, the Gateway can pass the
special applications according to the supplied information.
Assume, for example, that to use H.323 in a Net Meeting application, a local client starts a
session A to a remote host. The remote host uses session A to communicate with the local
host, but it also could initiate another session B back to the local host. Since there is only
session A recorded in the NAT session table when the local host starts the communication,
session B is treated as an illegal access from the outside and is blocked. Using the Special
Application menu, you can configure the Gateway to co-relate sessions A and B and
automatically open the port for the incoming session B.
To display the Port Triggering menu, click
Advanced
in the menu bar, and then click the
Port Triggering
submenu in the menu bar. Figure 48 shows an example of the menu.