Bringing Up A cisco Router Interface

 

Bringing Up A cisco Router Interface

When you are in Interface configuration face in your cisco router, it is important to not e that you can turn an interface on or even off, with few lines of commands.

The cisco router interface can be short down wth a simple command “ no shutdown “.

If an interface is shut down, it will automatically display administratively down when using the command Router#show interface , and the Router#show running-config command will show the interface as shutdown.

Note that all cisco router  interfaces are shut down by default.

Here are what they look like at first sight :

Router#sh int e0

Ethernet0 is administratively down, line protocol is down

You can simply Bring up an interface with the no shutdown command.

From the global configuration mode,

 

Enter configuration commands, one per line. End with

CNTL/Z.

Router#config t

Enter configuration commands, one per line. End with

CNTL/Z.

Router(config)#int e0

 Router(config-if)#no shutdown

 Router(config-if)#^Z

 Interface Ethernet0, changed state to up.

Line protocol on Interface

Ethernet0, changed state to up

 

Router#sh int e0

 

Ethernet0 is up, line protocol is up

 

Finally with this simple tutorial   you can now bring up a cisco router interface in a minute.

 

 

Lets add some more piece here by Configuring an IP Address on a cisco router Interface

Configuring an IP Address on a cisco router Interface

IP internet protocols are typically used on all routers.

 

To configure IP addresses on an interface, use the ip address command

from interface configuration mode.

 

Router(config)#int e0

 

Router(config-if)#ip address 172.16.10.2 255.255.255.0

 Router(config-if)#no shut

 Don’t forget to turn on an interface with the no shut command. Remember to look at the command show interface e0, for example, which will show you if it administratively shut down or not. Show running-config will also show you if the interface is shut down.

If you want to add a second subnet address to an interface, then you must use the secondary command.

If you type another IP address and press Enter, it will replace the existing IP address and mask. To add a secondary IP

address, use the secondary command.

Router(config-if)#ip address 192.168.1.2 255.255.255.0

secondary

Router(config-if)#^Z

 You can verify both addresses are configured on the interface with the

show running-config command (sh run for short).

Router#sh run

Building configuration…

Current configuration:

interface Ethernet0

 

ip address 192.168.1.2 255.255.255.0 secondary

ip address 192.168.1.2 255.255.255.0

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