Router – Access-lists
Below shows you a basic access-list configuration. R3>enableR3#configure terminalR3(config)#access-list 56 permit 192.12.10.3R3(config)#access-list 56 deny 192.12.10.0 0.0.0.255R3(config)#access-list 56 permit anyR3(config)#interface serial 0R3(config-if)#ip access-group 56 inR3(config-if)#exitR3(config)#exit