FVS338 ProSafe VPN Firewall 50 Re ference Manual
4-28 Firewall Protection and Content Filtering
v1.0, March 2008
4. To remove an entry from the table, select the IP/MAC Bind entry and click Delete.
5. Click Apply to save your settings.
Setting Up Port Triggering
Port triggering allows some applications running on a LAN network to be available to external
applications that would otherwise be partially blocked by the firewall. Using this feature requires
that you know the port numbers used by the Application.
Once configured, Port Triggering operates as follows:
1. A PC makes an outgoing connection using a port number defined in the Port Triggering table.
2. The VPN firewall records this connection, opens the an INCOMING port or ports associated
with this entry in the Port Triggering table, and associates them with the PC.
3. The remote system receives the PCs request and responds using the differen t port numbers that
you have now opened.
4. The VPN firewall 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:
• Only one 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 anothe r PC. This is required because this Router cannot be sure
when the application has terminated.
To add a Port triggering rule:
1. Select Security from the main menu and Port Triggering from the submenu. The Port
Triggering screen will display.
1. Enter a user-defined name for this rule in the Name field.
Note: For additional ways of allowing inbound traffic, see “LAN WAN Inbound
Services Rules” on page 4-9.