Configuring Port Triggering - NETGEAR FVX538v2 - ProSafe VPN Firewall Dual WAN Reference Manual

To edit an IP/MAC Bind rule, click Edit adjacent to the entry. The following fields of an existing
IP/MAC Bind rule can be modified:
• MAC Address. Specify the MAC Address for this rule.
• IP Addresses. Specify the IP Address for this rule.
• Log Dropped Packets. Specify the logging option for this rule.
To remove an entry from the table, select the IP/MAC Bind entry and click Delete.
To see the counter that shows the packets that were dropped because of IP-MAC binding
violations and to set the poll interval, click the Set Poll Interval link at the top of the IP/MAC
Binding screen.

Configuring Port Triggering

Port triggering allows some applications to function correctly that would otherwise be partially
blocked by the VPN firewall when it functions in NAT mode. Some applications require that when
external devices connect to them, they receive data on a specific port or range of ports. The VPN
firewall must send all incoming data for that application only on the required port or range of
ports. Using this feature requires that you know the port numbers used by the application.
Port triggering allows computers on the private network (LAN) to request that one or more ports
be forwarded to them. Unlike basic port forwarding which forwards ports to only one
preconfigured IP address, port triggering waits for an outbound request from the private network
on one of the defined outgoing ports. It then automatically sets up forwarding to the IP address that
sent the request. When the application ceases to transmit data over the port, the VPN firewall waits
for a timeout interval and then closes the port or range of ports, making them available to other
computers on the private network.
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 additional 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 different 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.
Firewall Protection and Content Filtering
ProSafe VPN Firewall 200 FVX538 Reference Manual
v1.0, January 2010
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