给网卡设备添加两个IP别名（一个网卡绑定多个ip）
首先执行ifconfig，查看网卡设备名称
[root@localhost conf]# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.3.128 netmask 255.255.255.0 broadcast 192.168.3.255
inet6 fe80::6b14:b58e:faa2:525 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:5e:7c:27 txqueuelen 1000 (Ethernet)
RX packets 46410 bytes 31588589 (30.1 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 25430 bytes 3803612 (3.6 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
可以看到网卡设备名称为ens33
下面我们给该设备添加ip别名
325 ifconfig ens33:1 192.168.3.123 broadcast 192.168.3.255 netmask 255.255.255.0 up
326 route add -host 192.168.3.123 dev ens33:1
327 ifconfig
328 ifconfig ens33:2 192.168.3.125 broadcast 192.168.3.255 netmask 255.255.255.0 up
329 route add -host 192.168.3.125 dev ens33:2
330 ifconfig
331 history
[root@localhost conf]# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.3.128 netmask 255.255.255.0 broadcast 192.168.3.255
inet6 fe80::6b14:b58e:faa2:525 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:5e:7c:27 txqueuelen 1000 (Ethernet)
RX packets 47199 bytes 31648090 (30.1 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 25448 bytes 3805064 (3.6 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens33:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.3.123 netmask 255.255.255.0 broadcast 192.168.3.255
ether 00:0c:29:5e:7c:27 txqueuelen 1000 (Ethernet)
ens33:2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.3.125 netmask 255.255.255.0 broadcast 192.168.3.255
ether 00:0c:29:5e:7c:27 txqueuelen 1000 (Ethernet)
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1 (Local Loopback)
RX packets 184495 bytes 29154176 (27.8 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 184495 bytes 29154176 (27.8 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255
ether 52:54:00:61:e7:bc txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@localhost conf]#
上面直接通过命令行配置的ip别名会在系统重启后失效，如果想让系统开机时自动运行，需要把那四条命令写入到/etc/rc.local文件里（该文件是系统启动时自动执行的文件）
这种方法执行的效果跟我们在虚拟机里面增加虚拟网卡后进行配置ip的效果是一样的
下面是我用物理机对这些ip进行ping的效果
root@BP:~# ping 192.168.3.128
PING 192.168.3.128 (192.168.3.128) 56(84) bytes of data.
64 bytes from 192.168.3.128: icmp_seq=1 ttl=64 time=0.280 ms
64 bytes from 192.168.3.128: icmp_seq=2 ttl=64 time=0.253 ms
^C
--- 192.168.3.128 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1004ms
rtt min/avg/max/mdev = 0.253/0.266/0.280/0.021 ms
root@BP:~# ping 192.168.3.125
PING 192.168.3.125 (192.168.3.125) 56(84) bytes of data.
64 bytes from 192.168.3.125: icmp_seq=1 ttl=64 time=0.357 ms
64 bytes from 192.168.3.125: icmp_seq=2 ttl=64 time=0.192 ms
^C
--- 192.168.3.125 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1022ms
rtt min/avg/max/mdev = 0.192/0.274/0.357/0.084 ms
root@BP:~# ping 192.168.3.123
PING 192.168.3.123 (192.168.3.123) 56(84) bytes of data.
64 bytes from 192.168.3.123: icmp_seq=1 ttl=64 time=0.266 ms
64 bytes from 192.168.3.123: icmp_seq=2 ttl=64 time=0.209 ms
^C
--- 192.168.3.123 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1030ms
rtt min/avg/max/mdev = 0.209/0.237/0.266/0.032 ms
