Configure a Local Loopback
Action
To configure a local loopback without physically connecting the transmit port to the receive port, follow these steps:
- In configuration mode, go to the following hierarchy level:[edit]user@host# edit interfaces interface-name (fastether-options | gigether-options)
- Configure the local loopback:[edit interfaces interface-name (fastether-options | gigether-options)] user@host# set loopback
- Verify the configuration:user@host# show
For example:
[edit interfaces fe-1/0/0 fastether-options]user@host# show loopback; - Commit the change:user@host# commit
For example:
[edit interfaces fe-1/0/0 fastether-options]user@host# commit commit complete
When you create a local loopback, you create an internal loop on the interface being tested. A local loopback loops the traffic internally on that PIC. A local loopback tests the interconnection of the PIC but does not test the transmit and receive ports. On an Ethernet interface, you cannot create a remote loopback, therefore there is no option to use a local or remote statement. Simply including the loopback statement at the [edit interfaces interface-name (fastether-options | gigether-options] hierarchy level, places the interface into local loopback mode.
![]() | Note: Remember to delete the loopback statement after completing the test. |


