See step 2; it's a matter of just clicking the firewall protection to OFF, from the "set up firewall protection" menu.

Set Up Firewall Protection
You can set up firewall filters and firewall alert notifications on your wireless home network. You
can also block Java Applets, Cookies, ActiveX controls, popup windows, Proxies, and website
access. See Protection Level for more information.
To set the firewall protection level:
1. From any screen, click the Firewall-Protection Level menu link or click the Firewall menu
button on the SBG6782-AC Main Menu and then select Protection Level.
Figure 17 - Firewall Protection Level Screen
2. Click the Firewall Protection Setting drop-down button to select the firewall protection level.
Possible values: Low, Medium, High, or Off
Note: Selecting Off will disable firewall protection on your home network. Your computer(s)
and other Ethernet-enabled devices on your network will be at risk for possible attacks from
viruses and hackers.
3. Select each Web filter that you want to set for the firewall and then click Apply.