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Management Ethernet Interfaces

Learn about the management Ethernet Interface, how to configure the IP address and MAC address on the management Ethernet interfaces.

Management interface in networking is a protocol and format that allows network operators to remotely access, configure, and control network devices. It provides a unified view of the managed device, which helps with consistent management. To connect to the router through the management port, use the management Ethernet interface.

Use Feature Explorer to confirm platform and release support for specific features.

Review the Platform-Specific Management Ethernet Interfaces Behavior section for notes related to your platform

Management Ethernet Interface Overview

The router’s management Ethernet interface, fxp0 or em0, is an out-of-band management interface that needs to be configured only if you want to connect to the router through the management port on the front of the router. You can configure an IP address and prefix length for this interface, which you commonly do when you first install the Junos OS:

To determine which management interface type is supported on a router, locate the router and Routing Engine combination in Supported Routing Engines by Router and note its management Ethernet interface type, either em0 or fxp0.

Alternatively, refer to the Day One + quick start guide for your platform at: Day One + Guides.

Configuring a Consistent Management IP Address

On routers with multiple Routing Engines, each Routing Engine is configured with a separate IP address for the management Ethernet interface. To access the primary Routing Engine, you must know which Routing Engine is active and use the appropriate IP address.

Optionally, for consistent access to the primary Routing Engine, you can configure an additional IP address and use this address for the management interface regardless of which Routing Engine is active. This additional IP address is active only on the management Ethernet interface for the primary Routing Engine. During switchover, the address moves to the new primary Routing Engine.

Note:

For M Series, MX Series, and most T Series routers, the management Ethernet interface is fxp0. For TX Matrix Plus routers and T1600 or T4000 routers configured in a routing matrix, the management Ethernet interface is em0.

Note:

Automated scripts that you have developed for standalone T1600 routers (T1600 routers that are not in a routing matrix) might contain references to the fxp0 management Ethernet interface. Before reusing the scripts on T1600 routers in a routing matrix, edit the command lines that reference the fxp0 management Ethernet interface so that the commands reference the em0 management Ethernet interface instead.

To configure an additional IP address for the management Ethernet interface, include the master-only statement at the [edit groups] hierarchy level.

In the following example, IP address 10.17.40.131 is configured for both Routing Engines and includes a master-only statement. With this configuration, the 10.17.40.131 address is active only on the primary Routing Engine. The address remains consistent regardless of which Routing Engine is active. IP address 10.17.40.132 is assigned to fxp0 on re0, and address 10.17.40.133 is assigned to fxp0 on re1.

This feature is available on all routers that include dual Routing Engines. On the TX Matrix router, this feature is applicable to the switch-card chassis (SCC) only.

See Also

Configuring the MAC Address on the Management Ethernet Interface

By default, the router’s management Ethernet interface uses as its MAC address the MAC address that is burned into the Ethernet card.

Note:

For M Series, MX Series, and most T Series routers, the management Ethernet interface is fxp0. For TX Matrix Plus routers and T1600 routers configured in a routing matrix, and TX Matrix Plus routers with 3D SIBs, T1600 routers, and T4000 routers configured in a routing matrix, the management Ethernet interface is em0.

Note:

Automated scripts that you have developed for standalone T1600 routers (T1600 routers that are not in a routing matrix) might contain references to the fxp0 management Ethernet interface. Before reusing the scripts on T1600 routers in a routing matrix, edit the command lines that reference the fxp0 management Ethernet interface so that the commands reference the em0 management Ethernet interface instead.

To display the MAC address used by the router’s management Ethernet interface, enter the show interface fxp0 or show interface em0 operational mode command.

To change the management Ethernet interface’s MAC address, include the mac statement at the [edit interfaces fxp0] or [edit interfaces em0] hierarchy level:

Specify the MAC address as six hexadecimal bytes in one of the following formats: nnnn.nnnn.nnnn (for example, 0011.2233.4455) or nn:nn:nn:nn:nn:nn (for example, 00:11:22:33:44:55).

Note:

If you integrate a standalone T640 router into a routing matrix, the PIC MAC addresses for the integrated T640 router are derived from a pool of MAC addresses maintained by the TX Matrix router. For each MAC address you specify in the configuration of a formerly standalone T640 router, you must specify the same MAC address in the configuration of the TX Matrix router.

Similarly, if you integrate a standalone T1600 router into a routing matrix, the PIC MAC addresses for the integrated T1600 router are derived from a pool of MAC addresses maintained by the TX Matrix Plus router. For each MAC address you specify in the configuration of a formerly standalone T1600 router, you must specify the same MAC address in the configuration of the TX Matrix Plus router.

See Also

Platform-Specific Management Ethernet Interfaces Behavior

Use Feature Explorer to confirm platform and release support for specific features.

Use the following table to review platform-specific behavior for your platform:

Platform

Difference

ACX Series

  • ACX Series routers that support management interface uses em0 as the management port for Junos OS platforms.

  • ACX Series routers that support management interface uses re0:mgmt-0 as the management port for Junos Evolved platforms.

MX Series

  • MX Series routers that support management interface uses fxp0 as the management port. The fxp0 interface is typically an RJ-45 port on the Routing Engine.

PTX Series

  • PTX Series routers that support management interface support two management interfaces per Routing Engine for Junos Evolved platforms. The two Routing Engines are identified as re0 and re1. The RJ-45 copper port on each Routing Engine is indexed as 0, while the SFP fiber port is indexed as 1.

    For example, the RJ-45 management Ethernet port on Routing Engine 0 is typically named re0:mgmt-0.