Configuring a router interface includes issuing the following commands:
Router>en
Router#config t
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#interface type-and-number
Router(config-if)#description description-text
Router(config-if)#ip address ipv4-address subnet-mask
Router(config-if)#ipv6 address ipv6-address/prefix-length
Router(config-if)#no shutdown
It is a good practice to use the description command to add information about the network connected to the interface. The no shutdown command activates the interface.
Following is a working example
Router>en
Router#config t
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#interface gigabitEthernet 0/0/0
Router(config-if)#description Link to LAN
Router(config-if)#ip address 192.168.10.1 255.255.255.0
Router(config-if)#ipv6 address 2001:db8:acad:10::1/64
Router(config-if)#no shutdown
Router(config-if)#
%LINK-5-CHANGED: Interface GigabitEthernet0/0/0, changed state to up
Router(config-if)#exit
Router(config)#
To verify interface configuration use the show ip interface brief and show ipv6 interface brief commands shown here:
Router#
Router#show ip interface brief
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0/0 192.168.10.1 YES manual up down
GigabitEthernet0/0/1 unassigned YES unset administratively down down
GigabitEthernet0/0/2 unassigned YES unset administratively down down
Vlan1 unassigned YES unset administratively down down
Router#
Router#show ipv6 interface brief
GigabitEthernet0/0/0 [up/down]
FE80::20C:85FF:FEEE:E801
2001:DB8:ACAD:10::1
GigabitEthernet0/0/1 [administratively down/down]
unassigned
GigabitEthernet0/0/2 [administratively down/down]
unassigned
Vlan1 [administratively down/down]
unassigned
