Port Triggering - Verizon HomeFusion Broadband User Manual

6 GUI: Firewall Settings
6.5

Port Triggering

Introduction
Port triggering can be used for dynamic port forwarding configuration. By setting
port triggering rules, inbound traffic is allowed to arrive at a specific network host
using ports different than those used for the outbound traffic. The outbound traffic
triggers which ports inbound traffic is directed to.
Example
Scenario
1 A local user accesses a remote gaming server using UDP protocol on port 2222.
2 The gaming server responds by connecting the user using UDP on port 3333
when starting gaming sessions.
Problem
 The firewall blocks inbound traffic by default. So the incoming message from the
game server (UDP:3333) will be blocked.
 If it would pass the firewall, the message will be addressed to the public IP
address of the HBR. Since the HBR did not have any previous UDP messages on
port 3333, it will not know to which device it should forward the message.
Solution
To solve this problem, we use port triggering. This means that if the HBR detects
traffic on the trigger port (in our case UDP:2222) it will automatically open a specific
port (in our example: UDP:3333).
The HBR will also know that if it receives a UDP message on port 3333 it should be
forwarded to the same device that sent a request via UDP port 2222.
Accessing the Port Triggering page
Proceed as follows:
1 On the top menu, click Firewall Settings.
2 The HBR prompts you to confirm your choice. Click Yes.
3 On the left menu, click Port Triggering.
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