Linux Network

if there are several network in a linux server, we can use the command ip addr to check the network interfaces.

and we can set visiting an ip via a specific network.

for example, I installed a external 5G device on a linux server, so there are two networks, I want to set visiting an IP via this 5G device.

check the network interfaces
```
 ip addr
```
check the routing table
```
 ip route
```

add a routing rule(temperary, will be lost after reboot)

 ip route add <destination_ip> via <gateway_ip> dev <network_interface>

for example:

 sudo ip route add 14.103.28.216 via 192.168.66.1 dev eno2

add a routing rule(persistent, will not be lost after reboot)

 vim /etc/netplan/01-netcfg.yaml

the content is like:

 network:
   version: 2
   ethernets:
     eno2:
       addresses: [192.168.66.88/24]
       gateway4: 192.168.66.1
       routes:
         - to: 14.103.28.216/32
           via: 192.168.66.1

then apply the netplan

 sudo netplan apply