前面测试的基于IP别名的IPAT接管中，逻辑网络中每个机器有2个网卡，这次测试是每个机器只要1个网卡

-bash-3.00# ifconfig -a
en0: flags=4e080863,80
        inet 12.0.0.61 netmask 0xffffff00 broadcast 12.0.0.255
en1: flags=4e080863,80
        inet 10.10.1.61 netmask 0xffffff00 broadcast 10.10.1.255
        inet 10.10.3.201 netmask 0xffffff00 broadcast 10.10.3.255
        inet 10.10.3.101 netmask 0xffffff00 broadcast 10.10.3.255
lo0: flags=e08084b
        inet 127.0.0.1 netmask 0xff000000 broadcast 127.255.255.255
        inet6 ::1/0
         tcp_sendspace 131072 tcp_recvspace 131072 rfc1323 1
-bash-3.00# rsh P61B ifconfig -a
en0: flags=4e080863,80
        inet 12.0.0.62 netmask 0xffffff00 broadcast 12.0.0.255
en1: flags=4e080863,80
        inet 10.10.1.62 netmask 0xffffff00 broadcast 10.10.1.255
        inet 10.10.3.202 netmask 0xffffff00 broadcast 10.10.3.255
        inet 10.10.3.102 netmask 0xffffff00 broadcast 10.10.3.255
lo0: flags=e08084b
        inet 127.0.0.1 netmask 0xff000000 broadcast 127.255.255.255
        inet6 ::1/0
         tcp_sendspace 131072 tcp_recvspace 131072 rfc1323 1

en1上的逻辑网络只配置了1个网卡，基于IP别名的IPAT

拔掉P61B的en1上的网线

-bash-3.00# ifconfig -a
en0: flags=4e080863,80
        inet 12.0.0.61 netmask 0xffffff00 broadcast 12.0.0.255
en1: flags=4e080863,80
        inet 10.10.1.61 netmask 0xffffff00 broadcast 10.10.1.255
        inet 10.10.3.201 netmask 0xffffff00 broadcast 10.10.3.255
        inet 10.10.3.101 netmask 0xffffff00 broadcast 10.10.3.255
        inet 10.10.3.102 netmask 0xffffff00 broadcast 10.10.3.255
lo0: flags=e08084b
        inet 127.0.0.1 netmask 0xff000000 broadcast 127.255.255.255
        inet6 ::1/0
         tcp_sendspace 131072 tcp_recvspace 131072 rfc1323 1

可以看到只需要一个网卡就搞定，而基于IP替换的IPAT必须要2个网卡