FirewallBuilder

Starting with Firewall Builder V4.2, it is possible to configure an interface's MTU (Maximum Transmission Unit). Currently this feature is only available on BSD (OpenBSD and FreeBSD) firewalls.

To configure an interface's MTU value, double-click the interface to open it for editing in the Editor Panel. Click the Advanced Interface Settings button. This will open the configuration window shown in Figure 9.8.

Figure 9.8. Modifying Interface MTU on a BSD Firewall

Click the checkbox called Set MTU and adjust the MTU to the desired value. Click OK.

For example, configuring this on interface eth0 will result in the following command being included in the generated firewall script.

ifconfig eth0 mtu 2500