Detailed explanation of basic operation commands for Linux network settings

View network configuration

View network interface information---ifconfig

View active network interface devices

ifconfig

View the specified network interface device

ifconfig network card name#You can view all existing network interfaces, including inactive ones

Replenish:

Inappropriate local MTU value When the local MTU value is greater than the network MTU value, the packet needs to be unpacked, which will lead to a decrease in efficiency. When the local MTU value is less than the network MTU value, the maximum transmission capacity is not utilized.

Ideal local MTU value Local MTU value = Network MTU value

View the routing table ---route

route [-n] #-n is to display the address in digital form

Check network connection status ---netstat

View the system's network connection status, routing table, interface statistics, and other information

netstat [options]

netstat -anpt #Displays all TCP information in the current system in digital form netstat -anpu #Displays all UDP information in the current system in digital form

Netstat can also be used with the pipe character and the grep command to filter out specific records.

Get socket statistics ---ss

Check the system's network connection status and obtain socket statistics.

The displayed content is similar to netstat, but ss can display more detailed information about TCP and connection status, and is faster and more efficient than netstat.

ss [options]

Test network connection

Test network connectivity ------ ping

ping [options] target host

In the linu system, the default ping is long and needs to be stopped by pressing Ctrl+C.

Test DNS domain name resolution ------nslookup

nslookup target host address [DNS server address]

Set network address parameters

In Linux system, there are two methods:

Temporary configuration---use commands to adjust network parameters

The modification takes effect immediately. It is simple and fast, and can directly modify the parameters of the running network. Generally, it is only suitable for use in the process of debugging the network. After the system is restarted, the modification will become invalid.

Fixed settings---Modify network parameters through configuration files

Modifying the configuration files of various network parameters is suitable for setting fixed parameters for the server. It will take effect only after reloading the network service or restarting.

Use command to modify (temporary configuration)

Modify the address and status of the network card------ifconfig

Set the IP address and subnet mask of the network interface

ifconfig network interface ip address [netmask subnet mask]
ifconfig network interface ip address [/subnet mask length] #Common

Disable or reactivate the network card

ifconfig network interface up 
ifconfig network interface down

Setting up a virtual network interface

It is generally used to temporarily use a new IP address on a network card in use, but the original IP address cannot be overwritten to cause some services to become unavailable. In this case, this command can be used to define a virtual network card bound to the original network card.

ifconfig network interface: serial number IP address

Add and delete static route records ---route

Add or delete routing records to a specified network segment

route add -net network segment address gw IP address route del -net network segment address

Add or delete default gateway records

It is best to have only one default route for the same host. If there are multiple default routes, it may affect the network.

route add default gw IP addressroute del default gw IP address

Modify the configuration file (fixed settings)

Network interface configuration files

Network interface configuration files are all in the /etc/sysconfig/network-scripts/ directory

To permanently modify the network interface information, you need to modify the network interface configuration file

vim /etc/sysconfig/network-scripts/ifcfg-ens33
TYPE=Ethernet #Set the network card type. "Ethernet" means Ethernet. DEVICE=ens33 #Set the name of the network card. ONBOOT=yes #Set whether the network card is activated when the Linux operating system starts. BOOTPROTO=static #Set the configuration method of the network card. "static" means using a static IP address. "dhcp" means obtaining the address dynamically. IPADDR=192.168.100.10 #Set the IP address of the network card. NETMASK=255.255.255.0 #Set the subnet mask of the network card. GATEWAY=192.168.100.2 #Set the default gateway address of the network card. DNS1=192.168.100.2 #Set the IP address of the DNS server.

Routing configuration files

Permanently add the route (restart the network service to take effect)

Method 1:

vim /etc/sysconfig/static-routes #Edit the /etc/sysconfig/static-routes file. No any net any gw 192.168.163.2 is automatically created. #The gateway of any network segment is 193.168.163.2
any net 192.168.3.0/24 gw 192.168.163.100 #The gateway of the 3.0/24 network segment is 193.168.163.100
any net 10.0.0.0 netmask 255.0.0.0 gw 192.168.163.2 #The gateway of the 10.0.0.0/8 network segment is 193.168.163.2
any host 192.168.100.100 gw 192.168.163.2 #The gateway of host 192.168.100.100 is 193.168.163.2

systemctl restart network #Restart the network service to make the previous configuration take effect

systemctl restart network #Restart the network service to make the previous configuration take effect

Method 2:

vim /etc/sysconfig/network-scripts/route-ens33
default via 192.168.163.2 dev ens33 #Default route, another format 0.0.0.0/0 192.168.14.254 dev ens33
10.0.6.0/24 via 192.168.163.2 dev ens33
192.168.100.200 via 192.168.14.254 dev ens33

systemctl restart network

Domain name resolution configuration file

vim /etc/resolv.conf 

Local host mapping file

The /etc/hosts file records the mapping relationship between the host name and the IP address.

Generally used to save information about hosts that are frequently accessed

Comparison of hosts file and DNS server

By default, the system first searches the hosts file for the resolution record.

The hosts file is only valid for the current host.

The hosts file can reduce the DNS query process and thus speed up access.

To set the hostname permanently:

hostnamectl set-hostname [hostname]
vim /etc/hostname #Only the first line is valid#After setting, you need to restart the system to take effect

Enable or disable network interface configuration:

systemctl restart network #Restart all network cards ifdown ens33 ; ifup ens33
ifdown ens33 #turn off a network cardifup ens33 #start a network cardifconfig ens33 down #temporarily disable a network cardifconfig ens33 up #reactivate a network card (will not update IP address)

This is the end of this article about the basic operation commands of Linux network settings. For more relevant Linux network settings content, please search for previous articles on 123WORDPRESS.COM or continue to browse the related articles below. I hope everyone will support 123WORDPRESS.COM in the future!