Linux下配置单网卡双IP的方法-马春杰杰

实验室的服务器线路大升级，由原来的静态IP升级为动态IP，直接走长清的线路，速度快的一匹，直接从百兆升级到千兆~

所以配置下动态IP和静态IP共存，方便两个IP段连接~

首先，查看目前的网卡情况：

(base) mcj@ubuntu:~$ ifconfig
docker0   Link encap:Ethernet  HWaddr 02:42:72:59:52:b3
          inet addr:172.17.0.1  Bcast:172.17.255.255  Mask:255.255.0.0
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

eno1      Link encap:Ethernet  HWaddr f4:02:70:9d:75:d4
          inet addr:172.16.150.201  Bcast:172.16.150.255  Mask:255.255.0.0
          inet6 addr: fe80::f602:70ff:fe9d:75d4/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:91498 errors:0 dropped:0 overruns:0 frame:0
          TX packets:108528 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:13131776 (13.1 MB)  TX bytes:38875180 (38.8 MB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:599 errors:0 dropped:0 overruns:0 frame:0
          TX packets:599 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1
          RX bytes:75328 (75.3 KB)  TX bytes:75328 (75.3 KB)

(base) mcj@ubuntu:~$ ifconfig

docker0 Link encap:Ethernet HWaddr 02:42:72:59:52:b3

inet addr:172.17.0.1 Bcast:172.17.255.255 Mask:255.255.0.0

UP BROADCAST MULTICAST MTU:1500 Metric:1

RX packets:0 errors:0 dropped:0 overruns:0 frame:0

TX packets:0 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:0

RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

eno1 Link encap:Ethernet HWaddr f4:02:70:9d:75:d4

inet addr:172.16.150.201 Bcast:172.16.150.255 Mask:255.255.0.0

inet6 addr: fe80::f602:70ff:fe9d:75d4/64 Scope:Link

UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

RX packets:91498 errors:0 dropped:0 overruns:0 frame:0

TX packets:108528 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1000

RX bytes:13131776 (13.1 MB) TX bytes:38875180 (38.8 MB)

lo Link encap:Local Loopback

inet addr:127.0.0.1 Mask:255.0.0.0

inet6 addr: ::1/128 Scope:Host

UP LOOPBACK RUNNING MTU:65536 Metric:1

RX packets:599 errors:0 dropped:0 overruns:0 frame:0

TX packets:599 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1

RX bytes:75328 (75.3 KB) TX bytes:75328 (75.3 KB)

可以看到，目前生效的网卡是eno1，接下来，打开/etc/network/interfaces文件，配置如下：

auto lo
iface lo inet loopback

auto eno1
iface eno1 inet dhcp
    dns-nameservers 119.29.29.29 8.8.8.8
    post-up ip addr add 172.16.150.201/24 dev eno1
    pre-down ip addr del 172.16.150.201/24 dev eno1

auto lo

iface lo inet loopback

auto eno1

iface eno1 inet dhcp

dns-nameservers 119.29.29.29 8.8.8.8

post-up ip addr add 172.16.150.201/24 dev eno1

pre-down ip addr del 172.16.150.201/24 dev eno1

配置之后，直接运行systemctl restart networking重启网络即可，或者reboot重启电脑~

最后使用ip addr show查看最新IP就行了~

(base) mcj@ubuntu:~$ ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether f4:02:70:9d:75:d4 brd ff:ff:ff:ff:ff:ff
    inet 10.170.3.9/16 brd 10.170.255.255 scope global eno1
       valid_lft forever preferred_lft forever
    inet 172.16.150.201/24 scope global eno1
       valid_lft forever preferred_lft forever
    inet6 fe80::f602:70ff:fe9d:75d4/64 scope link
       valid_lft forever preferred_lft forever
3: eno2d1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether f4:02:70:9d:75:d5 brd ff:ff:ff:ff:ff:ff
4: enp137s0f0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether a0:36:9f:ed:94:50 brd ff:ff:ff:ff:ff:ff
5: enp137s0f1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether a0:36:9f:ed:94:52 brd ff:ff:ff:ff:ff:ff
6: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
    link/ether 02:42:72:59:52:b3 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever

(base) mcj@ubuntu:~$ ip addr show

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

valid_lft forever preferred_lft forever

inet6 ::1/128 scope host

valid_lft forever preferred_lft forever

2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000

link/ether f4:02:70:9d:75:d4 brd ff:ff:ff:ff:ff:ff

inet 10.170.3.9/16 brd 10.170.255.255 scope global eno1

valid_lft forever preferred_lft forever

inet 172.16.150.201/24 scope global eno1

valid_lft forever preferred_lft forever

inet6 fe80::f602:70ff:fe9d:75d4/64 scope link

valid_lft forever preferred_lft forever

3: eno2d1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000

link/ether f4:02:70:9d:75:d5 brd ff:ff:ff:ff:ff:ff

4: enp137s0f0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000

link/ether a0:36:9f:ed:94:50 brd ff:ff:ff:ff:ff:ff

5: enp137s0f1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000

link/ether a0:36:9f:ed:94:52 brd ff:ff:ff:ff:ff:ff

6: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default

link/ether 02:42:72:59:52:b3 brd ff:ff:ff:ff:ff:ff

inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0

valid_lft forever preferred_lft forever

解释下：

当接口启动完成（完成 DHCP 获取地址之后）执行ip addr add 172.16.150.201/24 dev eno1 ，即在 eno1 接口上额外添加一个静态地址172.16.150.201，子网掩码 /24（255.255.255.0）。
- 这样 eno1 同时会有：
  - DHCP 分配的动态 IP
  - 手动加的 172.16.150.201 静态 IP（多地址共存）
在接口关闭（ifdown）前执行 pre-down ip addr del 172.16.150.201/24 dev eno1，这里是把在 post-up 里添加的那个静态 IP 删除掉，保持接口关闭后干净的状态。没有这一行的话，IP 可能会残留到下一次 up/down，也可能会造成网络冲突。