arp -a 是什么命令，有什么用意

用法：arp -a [inet_addr] [-N [if_addr]
命令解释：
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.
通过询问 TCP/IP 显示当前 ARP 项。如果指定了 inet_addr，则只显示指定计算机的 IP 和物理地址。