Cisco Router Interfaces:
In this cisco ccna lab we will explore and configure fast Ethernet interfaces and serial interfaces. For CCNA exam and network administration perspective it is necessary to know all the interfaces of a Cisco router and its configurations. Checking router interfaces play a great role in troubleshooting which often results in solving the connectivity problem by correcting the misconfigured interfaces of router. It is the responsibility of network engineer to monitor all the interfaces of a router for maintaining smooth functionality of the network.
Command for displaying all interfaces of a Cisco router is “show ip interface brief”
UPAAE > enable // for executing this command you need to be in enable mode. UPAAE # show ip interface brief
Assigning IP Address to Fast Ethernet Interface of Cisco Router:
In the above screenshot you have seen that none of the interfaces are configured, for assigning IP Address to a fast Ethernet port you have to be in global configuration mode. At global configuration mode enter this command “interface fa 0/0”.
This command has three parts 1 interface, 2 type of interface, 3 the port number.
The first part of this command is same for Ethernet and serial ports, the second part is where you have to specify whether you are configuring Serial interface or Ethernet interface(in our case we are going to configure IP address for Ethernet interface), “fa” stands for fast Ethernet. In the third part you have to specify the interface/port number in our case we are going to configure Ethernet port number 0/0.
If you don’t know the interface/ port number of your router run this command ”show ip interface brief” and note the specific interface number of concern.
Interface fa 0/0 will take you to the interface configuration mode where IP Address can be assigned to this interface. Follow the screenshot below.
UPAAE> enable UPAAE# configure terminal UPAAE(config)# interface fa 0/0 UPAAE(config-if)# ip address 10.1.1.2 255.0.0.0 UPAAE(config-if)# exit UPAAE(config)#
Assigning IP Address to Serial Interface of Cisco Router:
Serial interfaces of a cisco router are commonly used for connecting two routers back-to-back locally or connecting to the WAN. If you want to know more about the serial interfaces this will help you setting clock rate on serial interface. The command syntax for configuration of serial interface is same as the configuration of Ethernet interface but the variables in the command are different, the command structure will be “interface serial 0/0”. For knowing your Cisco router serial port numbers execute this command “show ip interface brief” from enable mode. Steps for assigning IP address to a serial interface is demonstrated in the following screenshot.
UPAAE> enable UPAAE# configure terminal UPAAE(config)# interface serial 0/0/0 UPAAE(config-if)# ip address 18.104.22.168 255.255.0.0 UPAAE(config-if)# exit UPAAE(config)#
Checking if IP Addresses are Properly Assigned:
I am always here to help, please do ask in comments for any problem regarding this tutorial.
Note: Even after a successful configuration of cisco router interface you will have to enable that interface for making it functional. As you can see in the above screenshot all the interfaces of cisco routers are by default administratively down. Also the students of ccna networking who are are preparing for ccna exam should give this point proper attention.
Recommended Resources for CCNA Exam:
Following resources are my personal recommendation for CCNA exam preparation, 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 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).