2.1-R1有默认网关：出接口 Proxy-ARP

3、验证：
（1）命令部署：
R2#debug arp
ARP packet debugging is on
R1#ping 3.3.3.3
（2）抓包验证：
R2#
Mar 1 00:02:48.191: IP ARP: rcvd req src 12.1.1.1 c001.1858.0000, dst 3.3.3.3 FastEthernet0/0
Mar 1 00:02:48.195: IP ARP: creating entry for IP address: 12.1.1.1, hw: c001.1858.0000
*Mar 1 00:02:48.195: IP ARP: sent rep src 3.3.3.3 c002.3430.0000,
dst 12.1.1.1 c001.1858.0000 FastEthernet0/0

R1#show arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 3.3.3.3 2 c002.3430.0000 ARPA FastEthernet0/0
Internet 12.1.1.1 - c001.1858.0000 ARPA FastEthernet0/0

2.1-R1有默认网关：出接口 Proxy-ARP

原文：http://blog.51cto.com/13856092/2137453