RIp V2 with No Auto- Summary :  In Above Scenario : on R2 interfaces major network's is diifrent but still in RIp V2 also they are advertised as classfull network's . To advertise them as classless we have to run no autosummary command on all three routers. R2(config)#router rip R2(config-router)#version 2 R2(config-router)#no auto-summary R2(config-router)#network 172.168.0.0 R2(conf... (more)

urpf stands for unicast reverse path forwarding .. It is used to prevent ip spoofing attacks.