LinuxShell_netmask

• config IP add

  ifconfig [interface_name] [param] // if means interface
  
  ifconfig eth0 up // eth0 means one of the Network Interface. 網卡
  
  ifconfig eth0 192.168.0.2 netmask 255.255.255.0
  

• param

   +---------+----------------------------------+
   |  param  |               features           |                  
   +---------+----------------------------------+
   |    up   |         init this interface.     |
   +---------+----------------------------------+
   |  down   |       terminate this interface.  |
   +---------+----------------------------------+
   | netmask |                                  |
   +---------+----------------------------------+
   |broadcast|                                  |
   +---------+----------------------------------+
   | mtu + N |                                  |
   +---------+----------------------------------+
   |metric+ N|                                  |
   +---------+----------------------------------+
   
   and there are also the params including:
   
   arp
   promisc mode
   allmulti
  

• example

  ✗ ifconfig
  
  lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> 
        mtu 16384
        options=1203<RXCSUM,TXCSUM,TXSTATUS,SW_TIMESTAMP>
        inet 127.0.0.1 // 網路位址
        netmask 0xff000000 //子網路遮罩
        
        inet6 ::1 
        prefixlen 128 
        inet6 fe80::1
        %lo0 
        prefixlen 64 
        scopeid 0x1 
        nd6 options=201<PERFORMNUD,DAD>
        
  gif0: flags=8010
        <POINTOPOINT,MULTICAST> 
        mtu 1280
  
  en0: flags=8863
        <UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> 
        mtu 1500
        options=400<CHANNEL_IO>
        ether 60:03:08:96:dd:bb //網卡卡號
        inet6 fe80::18a1:1e87:7a99:966c
        %en0 
        prefixlen 64 
        secured scopeid 0x4 
        inet 192.168.100.24 //網路位址
        netmask 0xffffff00 //子網路遮罩
        broadcast 192.168.100.255 //廣播
        
        nd6 options=201<PERFORMNUD,DAD>
        media: autoselect
        status: active
        
  awdl0: flags=8943
        <UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> 
        mtu 1484
        options=400<CHANNEL_IO>
        ether 0e:56:6b:69:99:66
        inet6 fe80::c56:6bff:fe69:9660% 
        awdl0 
        prefixlen 64 
        scopeid 0x9 
        nd6 options=201<PERFORMNUD,DAD>
        media: autoselect
        status: active
        
  llw0: flags=8863
         <UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> 
        mtu 1500
        options=400<CHANNEL_IO>
        ether 0e:56:6b:69:99:66 
        inet6 fe80::c56:6bff:fe69:9666
        %llw0 prefixlen 64 scopeid 0xa 
        nd6 options=201<PERFORMNUD,DAD>
        media: autoselect
        status: active
        
  utun0: flags=8051
        <UP,POINTOPOINT,RUNNING,MULTICAST> 
        mtu 1380
        inet6 fe80::6a93:5630:89ed:3e55
        %utun0 prefixlen 64 scopeid 0xb 
        nd6 options=201<PERFORMNUD,DAD>