I have configured R2 router NAT:R2(config)#ip route 0.0.0.0 0.0.0.0 s1/0R2(config)#access-list 10 permit 172.8.55.0 0.0.0.255R2(config)#ip nat inside source list 10 interface s1/0 overloadR2(config)#int s1/0R2(config-if)#ip nat outsideR2(config-if)#i...