Issue: Cisco Router Link Light Blinking Orange

The link light blinking orange on a Cisco router indicates a duplex mismatch error. In telecommunication, a duplex communication system refers to point-to-point communication and there are two types, namely full-duplex and half-duplex. In the half-duplex communication, only a single port can send or receive data at a time. On the other hand, in full-duplex, all nodes can send and receive data simultaneously. Continue reading this page to fix the issue Cisco router link light blinking orange.

Cisco's Router Link Light Blinking Orange Color

To fix the blinking orange link light on your Cisco router, follow the steps mentioned below.

Before starting, verify whether you have properly connected the network cable between the router and the switch.
If necessary, restart the router and reconnect the network cable to fix Cisco router link light blinking orange issue.
Next, enter into the global configuration mode of the router using the ‘S1# configure terminal’ command.
Use the ‘S1(config)# interface fastethernet 0/1’ command to enter the interface configuration mode.
Configure the interface duplex mode using the ‘S1(config-if)# duplex full’ command.
Next, type the ‘S1(config-if)# speed 100’ command to configure the interface speed.
Once completed, return to the privileged EXEC mode using the ‘S1(config)# end’ command.
To save the running configuration to the startup configuration, enter the ‘S1# copy running-config startup-config’ command in the Terminal window.
Doing so will fix the link light blinking problem on your Cisco router.

If the problem persists, enable the auto-MDIX (automatic medium dependent interface crossover) feature.

To do so, enter into global configuration mode and interface configuration mode.

Use the ‘S1(config-if)# duplex auto’ command to configure the interface to negotiate the duplex mode with the connected device automatically.

To automatically negotiate the speed with the connected devices, enter the ‘S1(config-if)# speed auto’ command.

To enable the auto-MDIX feature, enter ‘S1(config-if)# mdix auto’ in the Terminal window.

To exit and return to the privileged EXEC mode, enter ‘S1(config)# end’ in the Terminal window.

To save the running configuration to startup configuration, use the ‘S1# copy running-config startup-config’ command.

This will fix the Cisco router link light blinking orange issue.