Router>enable

Router#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)#int fa0/0

Router(config-if)#ip add 10.1.1.254 255.255.255.0

Router(config-if)#duplex full

Router(config-if)#speed 100

Router(config-if)#no shut

%LINK-3-UPDOWN: Interface FastEthernet0/0, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed

state to up

Router(config-if)#

Router(config-if)#do show run int fa0/0

Building configuration…

Current configuration : 94 bytes

interface FastEthernet0/0

 ip address 10.1.1.254 255.255.255.0

 duplex full

 speed 100

end

Router(config-if)#

Router(config-if)#exit

Router(config)#default interface fa0/0

Building configuration…

Interface FastEthernet0/0 set to default configuration

Router(config)#

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down

%LINK-3-UPDOWN: Interface FastEthernet0/0, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up

Rrouter(config)#do show run interface FastEthernet 0/0

Building configuration…

Current configuration : 73 bytes

!

interface FastEthernet0/0

 no ip address

 duplex auto

 speed auto

end

Router(config)#