In order to view all the interfaces available on any Cisco Router Interface or switch use (show ip interfaces brief) command.

Cisco Router Interface
Router Interfaces

In order to open the interface configuration mode, enter the following command (interface name _of interface).

Cisco Router Interface Configuration Mode
Interface Configuration Mode

Once you are in interface configuration mode variety of functions like assigning the IP address, Bandwidth, duplex, speed, and many other parameters can be configured. In order to assign the IP address, use the following command (Ip address X.X.X.X Y.Y.Y. Y) where X represents IP address and Y represents subnet mask.

Cisco Router Interface Assign IP Address to Interface
Assign IP Address to Interface

The description command is very useful it appears in the output of the following command (show Ip interfaces brief) that could be used as a reminder to identify which interface is being used for what purpose.

Cisco Description on Router Interface
The description on Router Interface

The configured configuration can be viewed from (show IP interfaces brief) or from (show running-config) command.

In order to shut down or disable the router interface run shut down command from interface configuration mode.

Disabling the Router InterfaceAll the interfaces by default are administratively in downstate in order to make them up using the No shutdown command.

Making the Interface Up

Also, read…

Setting the speed and duplex mode

The Giga Ethernet ports on Cisco 2941 router can run in both half and full duplex ,it also includes the feature of auto negotiation that that allows the router to auto-negotiate speed and duplex with corresponding interface on the other end of  connection .

Auto-negotiation is the default setting for the speed and transmission mode, when you are configuring interface speed and duplex follow the following guidelines.

  • If both end devices auto-negotiation, then use the default auto-negotiation setting.
  • When auto-negotiation is enabled, it automatically negotiates for speed and duplex mode.
  • If one end devices support auto-negotiation and the other side did not then configure them manually.
Configure Duplex Mode

Ip address on any routed interface can be configured either by using the command (Ip address X.X.X.X Y.Y.Y.Y) in interface configuration mode or it can be obtained from DHCP server by issuing the command (IP address DHCP).

Obtain IP Address from DHCP Server

Configuring the interface properties

Command Description


Router > enable

Enter the enable mode
Configure terminal


Router # Configure the terminal

Navigate to Global configuration mode
Interface slot/port


Router(config)# interface Fa0/0

Interface configuration mode
CDP enables


Router(config-if) CDP enable

To enable Cisco Discovery protocol
Ip address X.X.X.X Y.Y.Y. Y


Router(config-if) Ip address

Configure the IP address

Basic commands used for configuring Cisco router interfaces.

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