The physical port labeled Management (or for Firepower Threat Defense Virtual, the Management 0/0 virtual interface) actually has two separate interfaces associated with it.
- Management virtual interface—This IP address is used for system communication. This is the address the system uses for Smart Licensing and to retrieve database updates. You can open management sessions to it (Firepower Device Manager and CLI). You must configure a management address, which is defined on System Settings > Management Interface.
- Diagnostic physical interface—The physical Management port is actually named Diagnostic. You can use this interface to send syslog messages to an external syslog server. Configuring an IP address for the Diagnostic physical interface is optional. The only reason to configure the interface is if you want to use it for syslog. This interface appears, and is configurable, on the Device & Services > Interfaces page. The Diagnostic physical interface only allows management traffic, and does not allow through traffic.
(Hardware devices.) The recommended way to configure Management/Diagnostic is to not wire the physical port to a network. Instead, configure the Management IP address only, and configure it to use the data interfaces as the gateway for obtaining updates from the Internet. Then, open the inside interfaces to HTTPS/SSH traffic (by default, HTTPS is enabled) and open Firepower Device Manager using the inside IP address. This task you must perform on Firepower Device Manager directly. See "Configuring the Management Access List" in the Cisco Firepower Threat Defense Configuration Guide for Firepower Device Manager for instructions.
For Firepower Threat Defense Virtual, the recommended configuration is to attach Management0/0 to the same network as the inside interface, and use the inside interface as the gateway. Do not configure a separate address for Diagnostic.
Note: For special instructions on how to edit the Management interface see Cisco Firepower Threat Defense Configuration Guide for Firepower Device Manager for Firepower version 6.4 or higher. Open the guide and navigate to The Basic > Interfaces > Management/Diagnostic Interface. Management interface configuration should be done on the Firepower Device Manager.