When multiple network devices exist, how to configure their Internet access priority?

Common Internet peripherals include wired Ethernet 、WIFI、4G/5G Such as the interface , A hardware motherboard often carries multiple networks to access hardware resources . How to configure the use priority of different network peripherals ？ This article will introduce you to Linux Common configuration methods under the system .

Test environment ：HDG2L-IOT Assessment Kit , Equipped with dual Gigabit network 、4G CAT1 module ; function Ubuntu System , Kernel version 5.10 . See the following for specific operation steps .

 

chart 1 HDG2L-IOT Kit

1、 obtain IP Address

Network device acquisition IP Address . Fix IP Skip this step in mode , Automatically IP Perform the following operations in mode .

• Connect Ethernet ,wifi Connect to the network
• Use udhcpc -i eth0 -q command , Let the ether automatically find IP
• Enter into /home/wifi Catalog , perform wifi.sh, Give Way wifi Access router ; One gigabit network port is normally connected to the router .

2、 View the routing information table

Use route Command to view routing information , You can see Ethernet eth0 and wifi The Internet wlan0 The routing information of is generated automatically , And there are two default gateways . If you visit the Internet , The system will be based on the principle of optimal routing cache information and speed , Access through faster gateways .

 

chart 2 Routing table

3、 Modify gateway priority

Linux The system supports setting the priority of the default gateway , You need to use mteric This parameter . When there are multiple default gateways in the system , Packets will pass metric Lower interface transport , Usually , default metric All for 0, So the priority is the same .

Configure gateway priority is to configure the priority of network devices metric value , Let's do this for eth0 and wlan0 Set priorities separately .

• First of all, will metric The value is 0 The default gateway for is deleted ：

 

• Then reset the default gateway and metric：

 

• Finally using route Command view gateway , You can see wifi Of wlan0 And the ether eth0 Of metric The values of are 10 and 20, Configuration priority succeeded .

 

chart 3 Priority configuration

4、 Verification priority

There are many ways to verify priorities , Here is an easy-to-use method .

Use ping 114.114.114.114 -I wlan0 and ping 114.114.114.114 -I eth0 Commands can be obtained separately wlan0、eth0 Network delay , Use ping 114.114.114.114 You can get the network delay of the current default Internet device , The comparison of the two values can verify the configuration conclusion .

Be careful ： This method has limitations ,wlan0、eth0 Do not use this method when the network delay of is approaching .