On 05/08/10 15:25, Zhou Rui wrote: > What I want is finding a gateway out with ARP, and then assign the correct > gateway/route table,
You cant discover a router with ARP. ARP finds the MAC address of a host that's associated with a given IP address. Ways of getting a ipv4 gateway are; - manual configuration - DHCP - http://en.wikipedia.org/wiki/ICMP_Router_Discovery_Protocol