As a network administrator it is an everyday task to enable certain router interfaces and disable other for security measures, troubleshooting or testing network connectivity. In this quick tutorial i will show you the commands for enabling Cisco router interface and the command for administratively shutting down an interface of Cisco router.
Enabling a Cisco Router Interface:
You might be asking this question “why we need to enable an interface it should be working right after proper configuration”, but the fact is that Cisco devices does not automatically enable any interface unless they are given the command by network administrator. So by default all the network interfaces of a Cisco router are administratively down, when an interface is properly configured it should be enabled in order to perform its function.
Command for Enabling Cisco Router Interface:
As it’s an interface configuration command therefore you should be in the interface configuration mode of that specific interface which you want to enable.
UpaaeRouter1# configure terminal // if you are in enable mode go to global configuration mode UpaaeRouter1(config)# interface serial 0/0 // we are enabling serial interface 0 in module 0. UpaaeRouter1(config-if)# no shutdown upaaeRouter1(config-if)# end
Validate if a Router Interface is Enabled:
UpaaeRouter1 # show ip interface brief
Students preparing for Cisco CCNA exam should remember enabling an interface after configuring it, as configuring and interface is not enough to get it working you must have to enable it by executing “no shutdown” command
How to Administratively Shutdown an Interface:
By default all the interfaces of a Cisco router are in administratively shutdown state, even after configuring an interface it needs enabling. Administratively shutting down an interface is very useful command and it comes in handy when a network engineer want to remove a specific route from the routing table but keep all the configuration unaltered. Sometime for security reasons it is needed to disable sending and receiving data through a certain interface which is achieved by administratively shutting down that specific interface and saves us from all the trouble of removing cables etc.
Command for Administratively Shutting Down Router Interface:
For executing this command you need to be in interface configuration mode.
UpaaeRouter1# configure terminal // go to global configuration mode from enable mode UpaaeRouter1(config)# interface serial 0/0 // we want to shutdown serial interface 0 in module 0 UpaaeRouter1(config-if)# shutdown UpaaeRouter1(config-if)# end
Validate if Serial 0/0 interface is in Shut Down State:
UpaaeRouter1# show ip interface brief UpaaeRouter1# show interface serial 0/0 // this command will show you the details of serial 0/0 interface
Recommended Resources for CCNA Exam:
Following resources are my personal recommendations for Cisco CCNA exam preparation also for those who are seeking the profession of a network engineer, i know that i should recommend one best and most trusted resource but these are all my favorite, choosing only one among these great resources would be a biased decision according to my point of view. You can choose anyone from the following resources and i am 98% sure it will get you Cisco CCNA Routing and Switching certificate.
- CCNA Routing and Switching Complete Study Guide: Exam 100-105, Exam 200-105, Exam 200-125
- CCNA Routing and Switching 200-125 Official Cert Guide Library
- CCNA Routing and Switching Portable Command Guide (ICND1 100-105, ICND2 200-105, and CCNA 200-125)
- Cisco CCNA Simplified: Your Complete Guide to Passing the Cisco CCNA Routing and Switching Exam (Kindle Edition).