how to overwrite dns server setting from dhcp under linux

To overwrite DNS server settings from DHCP under Linux, you can use the following steps:

Open the terminal.
Edit the Network Manager configuration file using a text editor (e.g., nano or vi). The file is usually located at /etc/NetworkManager/NetworkManager.conf.
```
sudo nano /etc/NetworkManager/NetworkManager.conf
```
Look for the [main] section in the file and add the line dns=none. This line tells Network Manager not to use the DNS servers provided by DHCP.
```
[main]
dns=none
```
Save the file and exit the text editor.
Restart the Network Manager service to apply the changes.
```
sudo systemctl restart NetworkManager
```
Configure the DNS servers manually by editing the network interface configuration file. The file is usually located at /etc/sysconfig/network-scripts/ifcfg-<interface_name>. Replace <interface_name> with the name of your network interface (e.g., eth0).
```
sudo nano /etc/sysconfig/network-scripts/ifcfg-<interface_name>
```
Add the following lines to the file, replacing <DNS_server_IP> with the IP address of your desired DNS server(s).
```
DNS1=<DNS_server_IP>
DNS2=<DNS_server_IP>
```
You can add multiple DNS servers by specifying additional DNS3, DNS4, and so on.
Save the file and exit the text editor.
Restart the network service to apply the changes.
```
sudo systemctl restart network
```

After following these steps, your Linux system should now use the manually configured DNS servers and ignore the ones provided by DHCP