"IP" command to configure network interface

ipcommand is a new network command line tool,它用于在LInuxOne is allocated in the systemIPaddress to a network interface or configuration/Update useful network variables.它是iproute软件包的组成部分,And provides several network management tasks,Such as turning on or off a network interface,Assign and removeIP地址和路由,管理ARP缓存等.

[[email protected] ~]# dnf whatprovides "ip"
Last metadata expiration check: 2:42:10 ago on Mon 01 Aug 2022 07:45:22 PM CST.
iproute-5.15.0-4.el8.x86_64 : Advanced IP routing and network device configuration tools
Repo        : @System
Matched from:
Filename    : /usr/sbin/ip
Provide    : /sbin/ip

ipThe command is very similar to the old oneifconfig命令,But thanks to the addition of more features and abilities,It's much more powerful.ifconfigcommand in all modern timesLinuxhas been enabled in the distro and is ip命令替代.然而,ifconfigcommand for the most partlinuxReleases are still available.

注意：Please back up the configuration file before making any changes.

如何配置静态IPaddress network protocol(IPv4)

要在Linux中配置静态IP地址,You need to update or edit the network configuration file to assign a staticIPaddress to the system.You must be the one to usesuCommand superuser from terminal or command prompt.

对于RHEL/CentOS/Fedora和Rocky Linux/AlmaLinux

Open and edit the network configuration file with an editor.例如,分配IP地址给enp3s0接口.

[[email protected] ~]# vim /etc/sysconfig/network-scripts/ifcfg-enp3s0

输出结果：

TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=static
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=enp3s0
UUID=aed3f17e-747c-4a13-b421-407bb0a57f69
DEVICE=enp3s0
IPADDR=192.168.3.30
PREFIX=24
ONBOOT=yes

After setting the configuration,重启网络服务.

[[email protected] network-scripts]# systemctl restart NetworkManager.service

1、如何分配一个IPaddress to a specific port

The following commands will be used

[[email protected] ~]# ip addr add 192.168.3.31 dev enp3s0

to assign one immediatelyIPaddress to a specific interface(enp3s0).

[[email protected] ~]# ip addr show enp3s0
2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether c4:00:ad:54:a3:23 brd ff:ff:ff:ff:ff:ff
    inet 192.168.3.30/24 brd 192.168.3.255 scope global noprefixroute enp3s0
       valid_lft forever preferred_lft forever
    inet 192.168.3.31/32 scope global enp3s0
       valid_lft forever preferred_lft forever
    inet6 fe80::53ff:e021:58e4:1629/64 scope link noprefixroute
       valid_lft forever preferred_lft forever

2、如何检测IP地址

To get asIP地址、MACAddress information for the NIC interface information,使用以下命令.

[[email protected] ~]# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether c4:00:ad:54:a3:23 brd ff:ff:ff:ff:ff:ff
    inet 192.168.3.30/24 brd 192.168.3.255 scope global noprefixroute enp3s0
       valid_lft forever preferred_lft forever
    inet 192.168.3.31/32 scope global enp3s0
       valid_lft forever preferred_lft forever
    inet6 fe80::53ff:e021:58e4:1629/64 scope link noprefixroute
       valid_lft forever preferred_lft forever
...
8: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:19:0f:3d:c9:3d brd ff:ff:ff:ff:ff:ff
    inet 192.168.50.74/24 brd 192.168.50.255 scope global noprefixroute dynamic eno1
       valid_lft 86072sec preferred_lft 86072sec
    inet6 fe80::755d:a1a5:8380:e9f9/64 scope link noprefixroute
       valid_lft forever preferred_lft forever
...

3、How to remove oneIP地址

The following command will start from the specified interface(enp3s0)Remove an allocationIP地址.

[[email protected] ~]# ip addr del 192.168.3.30/24 dev enp3s0
[[email protected] ~]# ip addr show enp3s0
2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether c4:00:ad:54:a3:23 brd ff:ff:ff:ff:ff:ff
    inet 192.168.3.31/32 scope global enp3s0
       valid_lft forever preferred_lft forever
    inet6 fe80::53ff:e021:58e4:1629/64 scope link noprefixroute
       valid_lft forever preferred_lft forever

4、How to enable network interface

接口名称(enp3s0)的"up"The tag will enable a network interface.例如,The following command will activateenp3s0网卡接口.

[[email protected] ~]# ip link set enp3s0 down
[[email protected] ~]# ip addr show enp3s0
2: enp3s0: <BROADCAST,MULTICAST> mtu 1500 qdisc mq state DOWN group default qlen 1000
    link/ether c4:00:ad:54:a3:23 brd ff:ff:ff:ff:ff:ff

5、How to disable network interface

接口名称(enp3s0)的"down"Flag to disable a network interface.例如,The following commands will disableenp3s0网络接口.

[[email protected] ~]# ip link set enp3s0 up
[[email protected] ~]# ip addr show enp3s0
2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether c4:00:ad:54:a3:23 brd ff:ff:ff:ff:ff:ff
    inet 192.168.3.30/24 brd 192.168.3.255 scope global noprefixroute enp3s0
       valid_lft forever preferred_lft forever
    inet6 fe80::53ff:e021:58e4:1629/64 scope link noprefixroute
       valid_lft forever preferred_lft forever

6、How to detect routes

Enter the following command to detect the routing table information of the system.

[[email protected] ~]# ip route show
default via 192.168.50.1 dev eno1 proto dhcp metric 100
192.168.3.0/24 dev enp3s0 proto kernel scope link src 192.168.3.30 metric 101
192.168.50.0/24 dev eno1 proto kernel scope link src 192.168.50.74 metric 100
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1

7、How to add static routes

Why do you need to add static routes or manual routes,Because that traffic must not go through the default gateway.We need to add static routes so that traffic takes the best path to its destination.

[[email protected] ~]# ip route add 10.30.40.0/24 via 192.168.3.254 dev enp3s0
[[email protected] ~]# ip route show
default via 192.168.50.1 dev eno1 proto dhcp metric 100
10.30.40.0/24 via 192.168.3.254 dev enp3s0
192.168.3.0/24 dev enp3s0 proto kernel scope link src 192.168.3.30 metric 101
192.168.50.0/24 dev eno1 proto kernel scope link src 192.168.50.74 metric 100
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1

8、How to remove static routes

To remove the assigned static route,Just enter the following command.

[[email protected] ~]# ip route del 10.30.40.0/24
[[email protected] ~]# ip route show
default via 192.168.50.1 dev eno1 proto dhcp metric 100
192.168.3.0/24 dev enp3s0 proto kernel scope link src 192.168.3.30 metric 101
192.168.50.0/24 dev eno1 proto kernel scope link src 192.168.50.74 metric 100
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1

9、How to add permanent static route

在系统重启后,All the above routes will be lost.To add permanent static routes,编辑文件/etc/sysocnfig/network-scripts/route-enp3s0.

[[email protected] network-scripts]# cat route-enp3s0
10.30.40.0/24 via 192.168.3.254 dev enp3s0

接着,After entering all the details using the command,重启网络服务.

[[email protected] network-scripts]# systemctl restart NetworkManager
[[email protected] network-scripts]# ip route show
default via 192.168.50.1 dev eno1 proto dhcp metric 100
10.30.40.0/24 via 192.168.3.254 dev enp3s0
192.168.3.0/24 dev enp3s0 proto kernel scope link src 192.168.3.30 metric 101
192.168.50.0/24 dev eno1 proto kernel scope link src 192.168.50.74 metric 100
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1

10、How to add default gateway

The default gateway can be specified globally or for an interface-specific configuration file.The advantage of default gateway is if we have multiple network cards in the system.You can immediately add the default gateway with the following command.

[[email protected] network-scripts]# ip route add default via 192.168.3.254
[[email protected] network-scripts]# ip route show
default via 192.168.3.254 dev enp3s0
default via 192.168.50.1 dev eno1 proto dhcp metric 100
10.30.40.0/24 via 192.168.3.254 dev enp3s0
192.168.3.0/24 dev enp3s0 proto kernel scope link src 192.168.3.30 metric 101
192.168.50.0/24 dev eno1 proto kernel scope link src 192.168.50.74 metric 100
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1

11、How to remove the default gateway

The default gateway can be deleted with the following command.

[[email protected] network-scripts]# ip route del default via 192.168.3.254
[[email protected] network-scripts]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.50.1    0.0.0.0         UG    100    0        0 eno1
10.30.40.0      192.168.3.254   255.255.255.0   UG    0      0        0 enp3s0
192.168.3.0     0.0.0.0         255.255.255.0   U     101    0        0 enp3s0
192.168.50.0    0.0.0.0         255.255.255.0   U     100    0        0 eno1
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0