[to]12 common IP commands in the iproute installation package

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This tutorial will discuss  ip  Ordered 12 The most commonly used method in , Let's get started .

Case study 1： Check network card information

Check the network card, such as IP Address , Subnet and other network information , Use  ip addr show  command ：

[[email protected]]$ ip addr show or [[email protected]]$ ip a s

This will display the relevant network information of all available network cards in the system , But if you want to check the information of a network card , The order is ：

[[email protected]]$ ip addr show enp0s3

here  enp0s3  It's the name of the network card .

IP-addr-show-commant-output

Case study 2： Enable / Disable network card

Use  ip  Command to enable a disabled network card ：

[[email protected]]$ sudo ip link set enp0s3 up

To disable the network card, use  down  trigger ：

[[email protected]]$ sudo ip link set enp0s3 down

Case study 3： Assign... To the network card IP Address and other network information

To assign... To the network card IP Address , We use the following command ：

[[email protected]]$ sudo ip addr add 192.168.0.50/255.255.255.0 dev enp0s3

You can also use  ip  Command to set the broadcast address . The default is that no broadcast address is set , The command to set the broadcast address is ：

[[email protected]]$ sudo  ip addr add broadcast 192.168.0.255 dev enp0s3

We can also use the following command according to IP Address set the standard broadcast address ：

[[email protected]]$  sudo ip addr add 192.168.0.10/24 brd + dev enp0s3

As the example above shows , We can use  brd  Instead of  broadcast  To set the broadcast address .

Case study 4： Delete the configured in the network card IP Address

If you want to delete a from your network card IP, Use as follows  ip  command ：

[[email protected]]$ sudo ip addr del 192.168.0.10/24 dev enp0s3

Case study 5： Add an alias for the network card （ Suppose the network card name is enp0s3）

Add alias , That is, add more than one network card IP, Execute the following command ：

[[email protected]]$  sudo ip addr add 192.168.0.20/24 dev enp0s3 label enp0s3:1

ip-command-add-alias-linux

Case study 6： Check the routing / Information about the default gateway

Viewing the routing information will show us the routing path of the packet to the destination . To view network routing information , Execute the following command ：

[[email protected]]$  ip route show

ip-route-command-output

In the output above , We can see the routing information of packets on all network cards . We can also get specific IP Routing information for , The method is ：

[[email protected]]$ sudo ip route get 192.168.0.1

Case study 7： Add static route

We can also use IP To modify the default routing of packets . The method is to use  ip route  command ：

[[email protected]]$ sudo ip route add default via 192.168.0.150/24

In this way, all network packets pass through  192.168.0.150  To forward , Instead of the previous default route . To modify the default route of a network card , perform ：

[[email protected]]$ sudo ip route add 172.16.32.32 via 192.168.0.150/24 dev enp0s3

Case study 8： Delete default route

To delete the previously set default route , Open the terminal and run ：

[[email protected]]$  sudo ip route del 192.168.0.150/24

Be careful ：  The default route modified by the above method is only temporarily valid , All changes will be lost after the system restarts . To permanently modify the route , Need to modify or create  route-enp0s3  file . Add the following line ：

[[email protected]]$  sudo vi /etc/sysconfig/network-scripts/route-enp0s3172.16.32.32 via 192.168.0.150/24 dev enp0s3

Save and exit the file .

If you are using based on Ubuntu or debian Operating system of , Then the file to be modified is  /etc/network/interfaces, Then add  ip route add 172.16.32.32 via 192.168.0.150/24 dev enp0s3  This line goes to the end of the file .

Case study 9： Check all ARP Record

ARP, It's address resolution protocol Address Resolution Protocol Abbreviation , Is used to IP Address translation to physical address （ That is to say MAC Address ）. be-all IP Corresponding to it MAC Details are stored in one table , This table is called ARP cache .

To see ARP Records in cache , That is, the device connected to the LAN MAC Address , Use the following ip command ：

[[email protected]]$  ip neigh

ip-neigh-command-linux

Case study 10： modify ARP Record

Delete ARP The recorded command is ：

[[email protected]]$ sudo ip neigh del 192.168.0.106 dev enp0s3

If you want to go ARP Add a new record to the cache , The order is ：

[[email protected]]$ sudo ip neigh add 192.168.0.150 lladdr 33:1g:75:37:r3:84 dev enp0s3 nud perm

here  nud  It means “neghbour state”（ Network neighborhood status ）, Its value can be ：

• perm - It is permanently valid and can only be deleted by the administrator
• noarp - Record valid , But it is allowed to be deleted after the life cycle expires
• stale - Record valid , But it may have expired
• reachable - Record valid , But it will be invalid after timeout

Case study 11： View network statistics

adopt  ip  The command can also view network statistics , For example, the number of bytes and messages transmitted on all network cards , Number of erroneous or discarded messages, etc . Use  ip -s link  Order to see ：

[[email protected]]$ ip -s link

ip-s-command-linux

Case study 12： get help

If you want to see an option that is not in the above example , Then you can check the help . In fact, you can ask for help with any order . To list  ip  All options of the command , perform ：

[[email protected]]$ ip help