# Example: adding an additional interface to a Single Engine element

An example of adding an interface to a Single Engine.

In the previous example, the administrator initially configured the engine at the company’s new branch office with just two interfaces. Now the administrator decides to add a physically separated DMZ network for access to/from that office’s mail server to properly control both internal and external traffic with this publicly exposed server. The administrator:

1. Creates an interface for the DMZ and gives it the following properties:
   - Interface ID: 2
   - IP Address: 192.168.2.1.
2. Creates new rules in the engine’s policy to allow traffic to/from the DMZ and NAT rules to translate between the private and public IP address of the mail server.
3. Connects the new DMZ router to the engine.
4. Installs a Engine Policy using the SMC Client to transfer the new working configuration to the Engine.