Firepower 1100 Threat Defense Getting Started: Management Center on a Local Management Network

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Configure interfaces

Updated: March 20, 2026

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Overview

Learn how to configure Firepower 1100 interfaces, including assigning inside and outside zones and setting IP addressing for routed deployments.

When you use the Firewall Device Manager for initial setup, the following interfaces are preconfigured:

  • Ethernet 1/1—outside, IP address from DHCP, IPv6 autoconfiguration

  • Ethernet 1/2— inside, 192.168.95.1/24

  • Default route—Obtained through DHCP on the outside interface

If you performed additional interface-specific configuration within Firewall Device Manager before registering with the Firewall Management Center, then that configuration is preserved.

The following example configures a routed-mode inside interface with a static address and a routed-mode outside interface using DHCP. It also adds a DMZ interface for an internal web server.

Procedure

1.

Choose Devices > Device Management, and click Edit (edit icon) for the firewall.
2.

Click Interfaces.

Figure 1. Interfaces
Interfaces
3.

Click Edit (edit icon) for the interface that you want to use for inside.

Figure 2. General Tab
General Tab

  1. From the Security Zone drop-down list, choose an existing inside security zone or add a new one by clicking New.

    For example, add a zone called inside_zone. You apply your security policy based on zones or groups. For example, configure your access control policy to enable traffic to go from the inside zone to the outside zone, but not from outside to inside.

    If the inside interface was preconfigured, the rest of these fields are optional.

  2. Enter a Name up to 48 characters in length.

    For example, name the interface inside.

  3. Check the Enabled check box.

  4. Leave the Mode set to None.

  5. Click the IPv4 and/or IPv6 tab.

    • IPv4—Choose Use Static IP from the drop-down list, and enter an IP address and subnet mask in slash notation.

      For example, enter 192.168.1.1/24

      Figure 3. IPv4 Tab
      IPv4 Tab

    • IPv6—Check the Autoconfiguration check box for stateless autoconfiguration.

      Figure 4. IPv6 Tab
      IPv6 Tab

  6. Click OK.
4.

Click Edit (edit icon) for the interface that you want to use for outside.

Figure 5. General Tab
General Tab

  1. From the Security Zone drop-down list, choose an existing outside security zone or add a new one by clicking New.

    For example, add a zone called outside_zone.

    If the outside interface was pre-configured, the rest of these fields are optional.

  2. Enter a Name up to 48 characters in length.

    For example, name the interface outside.

  3. Check the Enabled check box.

  4. Leave the Mode set to None.

  5. Click the IPv4 and/or IPv6 tab.

    • IPv4—Choose Use DHCP, and configure the following optional parameters:

      • Obtain default route using DHCP—Obtains the default route from the DHCP server.

      • DHCP route metric—Assigns an administrative distance to the learned route, between 1 and 255. The default administrative distance for the learned routes is 1.

      Figure 6. IPv4 Tab
      IPv4 Tab

    • IPv6—Check the Autoconfiguration check box for stateless autoconfiguration.

      Figure 7. IPv6 Tab
      IPv6 Tab

  6. Click OK.
5.

Configure a DMZ interface to host a web server, for example.

  1. Click Edit (edit icon) for the interface you want to use.

  2. From the Security Zone drop-down list, choose an existing DMZ security zone or add a new one by clicking New.

    For example, add a zone called dmz_zone.

  3. Enter a Name up to 48 characters in length.

    For example, name the interface dmz.

  4. Check the Enabled check box.

  5. Leave the Mode set to None.

  6. Click the IPv4 and/or IPv6 tab and configure the IP address as desired.

  7. Click OK.
6.

Click Save.