Cisco Router Interfaces Configurations

Cisco Router Interface configuration is one of the most important configurations of the router. Without interfaces, I would rather say that the router is useless.

Cisco Router Interface configurations should in a way that it will directly communicate with other devices.

Some of the Cisco Router configurations parameters used to configure an interface are Network layer addresses, media type, bandwidth, and

cisco router interface configurations

other administrative commands.

It should be noted that several cisco routers uses different methods to choose interfaces used on a router.

Let assume we are configuring a cisco 2500 series router,  the following command show will show us the  router with 10 serial interfaces, which are labeled 0 through 9:

check for routing protocol configuration

Router(config)#int serial ?


<0-9> Serial interface number


As soon as we are here on this command we have to choose the interface we  want to configure and input our necessary parameters.

After that the router will then keep us on that interface Once you do tht for further  configuration of  that particular interface.


The command to choose serial port 5, for example, would be


Router(config)#int serial 5


Router(config)-if)# ethernet 0 can configure the interface.


Router(config)#int ethernet ?


<0-0> Ethernet interface number


Router(config)#int ethernet 0




To configure an interface, you always use the interface type number sequence.

However, cisco made interface configurations easy on the 2600, 3600, 4000, and 7000 series routers hence they uses a physical slot in the router and a port number on the module plugged into that slot.


For instance, on a 2600 series  router, the configuration would be interface type slot/port:


Router(config)#int fastethernet ?


<0-1> FastEthernet interface number


Router(config)#int fastethernet 0


When input theis command the router will show


% Incomplete command.

So recall to put the question mark


Router(config)#int fastethernet 0?


Router(config)#int fastethernet 0/?


<0-1> FastEthernet interface number


Notice that you cannot type int fastethernet 0. You must type the full

command, which is type slot/port, or int fastethernet 0/0. You can

type int fa 0/0 as well.

To set the type of connector used, use the command media-type. However, this is typically auto-detected in routers.


Router(config)#int fa 0/0


Router(config-if)#media-type ?


100BaseX Use RJ45 for -TX; SC FO for –FX

how to set banners on cisco routers

MII Use MII connector

Next we will talking about bringing up a cisco router interface in my next post.

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