**Routers overview:**

{{:routers.jpg?500|}}

**Entering into a configuration mode:**

<sxh bash>
conf t
</sxh>

**Configuring a certain Interface:**

<sxh bash>
Router1#conf t
Router1(config)#int fa0/0
Router1(config-if) #ip add 180.0.3.1 255.255.255.0
Router1(config-if) #no sh
Router1(config-if) #exit
Router1(config)#int fa0/1
Router1(config-if) #ip add 180.0.7.1 255.255.255.0
Router1(config-if) #no sh
Router1(config-if) #exit
Router1(config)#int fa1/0
Router1(config-if) #ip add 180.0.2.1 255.255.255.0
Router1(config-if) #no sh
Router1(config-if) #exit
Router1(config)#exit
Router1#wr

Router2#conf t
Router2(config)#int fa0/0
Router2(config-if) #ip add 180.0.3.2 255.255.255.0
Router2(config-if) #no sh
Router2(config-if) #exit
Router2(config)#int fa0/1
Router2(config-if) #ip add 180.0.5.1 255.255.255.0
Router2(config-if) #no sh
Router2(config-if) #exit
Router2(config)#int fa1/0
Router2(config-if) #ip add 180.0.4.1 255.255.255.0
Router2(config-if) #no sh
Router2(config-if) #exit

Router3#conf t
Router3(config)#int fa0/0
Router3(config-if) #ip add 180.0.5.2 255.255.255.0
Router3(config-if) #no sh
Router3(config-if) #exit
Router3(config)#int fa0/1
Router3(config-if) #ip add 180.0.6.1 255.255.255.0
Router3(config-if) #no sh
Router3(config-if) #exit
Router3(config)#exit
Router3#wr

Router4#conf t
Router4(config)#int fa0/0
Router4(config-if) #ip add 180.0.6.2 255.255.255.0
Router4(config-if) #no sh
Router4(config-if) #exit
Router4(config)#int fa0/1
Router4(config-if) #ip add 180.0.7.2 255.255.255.0
Router4(config-if) #no sh
Router4(config-if) #exit
Router4(config)#exit
Router4#wr
</sxh>

Show the settings:

<sxh bash>
R1#sh ip interface brief
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            180.0.2.1       YES manual up                    up
</sxh>