询问了下Windows Client TechCenter,其中一个Moderator回答了我:
"Maybe you were trying to add a new IP-to-MAC record for an existed IP address or MAC address. We are not able to realize it with arp commands in Windows 7. "
原来windows7不支持用arp添加已经绑定了的地址,看来arp不行,只能拿起万能而且万恶的netsh了,
netsh interface ipv4 set neighbors 12 "57.55.85.212" "00-aa-00-62-c6-09" store=active
注意:12是网卡序号,需要运行前先查下。