arp.exe 是一个管理网卡底层物理地址的程序，每个网卡都有一个全球优异的物理地址，上网时，动态的IP地址就是根据这个物理地址影射的。
在同一个局域网段内有两个物理地址相同的网络适配器，不论如何配置都会造成IP地址冲突。
arp -a,显示arp的影射；
arp -s IP地址 物理地址，增加一个arp影射，如arp -s 192.168.1.1 00-aa-00-00-c2
-99；
arp -d IP地址 物理地址，del掉一个arp影射。
用法：当IP地址冲突时，使用此命令可以把冲突的IP地址屏蔽掉！
详细用法：
Displays and modifies the IP-to-Physical address translation tables used by
address resolution protocol (ARP).
ARP -s inet_addr eth_addr [if_addr]
ARP -d inet_addr [if_addr]
ARP -a [inet_addr] [-N if_addr]
  -a      Displays current ARP entries by interrogating the current
          protocol data.  If inet_addr is specified, the IP and Physical
          addresses for only the specified computer are displayed.  If
          more than one network interface uses ARP, entries for each ARP
          table are displayed.
  -g      Same as -a.
  inet_addr     Specifies an internet address.
  -N if_addr    Displays the ARP entries for the network interface specified
                by if_addr.
  -d            Deletes the host specified by inet_addr.
  -s            Adds the host and associates the Internet address inet_addr
                with the Physical address eth_addr.  The Physical address is
                given as 6 hexadecimal bytes separated by hyphens. The entry
                is permanent.
  eth_addr      Specifies a physical address.
  if_addr       If present, this specifies the Internet address of the
                interface whose address translation table should be modified.
                If not present, the first applicable interface will be used.

Example:
  > arp -s 157.55.85.212   00-aa-00-62-c6-09  .... Adds a static entry.
  > arp -a                  .... Displays the arp table.

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