Linux Network basic configuration and troubleshooting methodology

(I) basic configuration commands

In Linux, the Ethernet interface is run with the following commands: eth0 and eth1; 0 and 1 represent the nic id.
Use lspci to view the hardware information of the NIC. If it is a USB Nic, use the lsusb command.
Ifconfig is used to view interface information.
Ifconfig-a view all interfaces
Ifconfig eth0 view specific Interfaces
IFUP and ifdown are used to enable or disable an interface.
IFUP eth0
Ifdown eth0
Configure Network Information in setup Gui
Enable the NIC with IFUP after the configuration is complete, and use ifconfig to view information



(Ii) network-related configuration files

Nic configuration file
/Etc/sysconfig/network-scripts/ifcfg-eth0
DNS configuration file
/ETH/resolv. conf
Host Name configuration file
/Etc/sysconfig/Network
Modify host name in real time
-- No after restart
Hostname think. localdomain
Permanent modification of Host Name
-- Takes effect after restart
/Etc/sysconfig/Network

(Iii) Network Test commands

Test network connectivity
-- IP address, subnet mask, and network hardware
Ping 192.168.1.1 test Gateway
Ping www.csdn.net
Test DNS resolution
Simple: Host www.csdn.net
Complex: Dig www.csdn.net
Show route table
-- Each host has its own route table.
IP Route
Track the network path to the target address
-- That is, the number of routers and their addresses
Traceroute www.csdn.net
Network Quality Test
-- Combined with Traceroute and Ping
MTR www.csdn.net


(Iv) network troubleshooting

Principle: bottom-up
From inside out



① Check whether the network configuration is correct.

● IP Address
● Subnet Mask
● Gateway
● DNS

② Check whether the gateway is connected
Ping the gateway/Target IP Address

③ Check whether DNS resolution is correct
Host www.douban.com
Host www.csdn.net