Configure a Modem Interface

To use a modem with your Firebox, connect the modem to your Firebox and power the modem on.

In Fireware v12.1.1 and higher, you can hot plug modems into the Firebox. The modem operates and does not require a Firebox reboot when:

  • You plug in a new modem
  • You unplug a modem and plug it in again
  • The modem unexpectedly disconnects and reconnects to the Firebox

About 4G LTE and 5G

On the Firebox T80 and T85, you can connect to a 4G LTE cellular network with an LTE interface module. On the Firebox T45-CW, you can connect to a cellular network with the integrated 5G modem. This enables you to install a SIM card and use the cellular connection as an external interface on the Firebox for primary or backup WAN connectivity.

For more information, go to Configure a 4G LTE or 5G Modem.

You cannot use a USB modem at the same time as the LTE interface module on the Firebox T80 and T85, or on the T45-CW that has an integrated 5G modem.

Account Settings

To configure the account settings for your modem, from Fireware Web UI or Policy Manager:

  1. Select Network > Modem.
  2. Make sure that the Enable Modem check box is selected.
  3. From the Modem Type drop-down list, select the type of modem to configure.

Enable Modem Failover Debug Log Messages

If you have problems with your connection, you can enable your Firebox to send detailed log messages to the event log file when a modem failover occurs. You can then review the debug log messages to find any errors.

On the Account tab, select the Enable modem and PPP debug trace check box.

DNS Settings 

If your ISP or wireless service provider does not provide DNS server information, or if you must use a different DNS server, you can manually add the IP addresses for a DNS server.

The MTU setting applies only to modems with PPP configurations.

Other DNS servers configured on your Firebox might take precedence over DNS servers obtained from your ISP or specified in the modem settings. For more information about DNS on the Firebox, go to About DNS on the Firebox.

Dial-Up Settings

Advanced Settings

Some dial-up ISPs or wireless service providers require that you specify one or more PPP options before you can connect. In China, for example, some ISPs require that you use the PPP option receive-all. The receive-all option forces PPP to accept all control characters from the peer.

Link Monitor

To prevent unwanted bandwidth consumption, link monitor is not enabled for modem interfaces by default. For more information about link monitor, go to About Link Monitor.

To configure link monitor targets for modem interfaces:

Fireware v12.3 or higher

From the Web UI, select Network > Link Monitor.

From Policy Manager, select Network > Configuration > Link Monitor.

Fireware v12.1 to v12.2.1

Link monitor settings for modems appear in the multi-WAN settings. For information about how to configure link monitor in Fireware v12.1 to v12.2.1, go to Configure Link Monitor in Fireware v12.1 to v12.2.1 in the WatchGuard Knowledge Base.

Fireware v12.0.2 or lower

Link monitor settings for modems appear in the modem configuration settings. For information about how to configure link monitor in Fireware v12.0.2 and lower, go to Configure Modem Failover in Fireware v12.0.2 and lower in the WatchGuard Knowledge Base.

Related Topics

About Modem Interfaces

Configure a 4G LTE or 5G Modem

Configure Modem Failover

Configure VPN Modem Failover

About Multi-WAN