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
