ifconfig -a

eth0: flags=4163 mtu 1500

    inet xxx.xxx.xxx.xxx  netmask 255.255.240.0  broadcast xxx.xxx.xxx.xxx
    ether 00:16:3e:03:bf:12  txqueuelen 1000  (Ethernet)
    RX packets 122915  bytes 178384892 (170.1 MiB)
    RX errors 0  dropped 0  overruns 0  frame 0
    TX packets 63977  bytes 4457624 (4.2 MiB)
    TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73 mtu 65536

    inet 127.0.0.1  netmask 255.0.0.0
    loop  txqueuelen 1  (Local Loopback)
    RX packets 36  bytes 4968 (4.8 KiB)
    RX errors 0  dropped 0  overruns 0  frame 0
    TX packets 36  bytes 4968 (4.8 KiB)
    TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

为什么我在系统里面只能看到一块网卡？公网IP地址的那块看不到。