Using a customer nameserver often requires disabling the DHCP based resolv.conf modifications. Here is what I got to work.
I needed to modify the connection associated with the Ethernet device. In my case, this was called “System eth0”. The two values I needed to change were: ipv4.ignore-auto-dns (from no to yes) and the ipv4.dns value, setting the desired DNS servers.
Here were the commands.
nmcli conn modify "System eth0" ipv4.ignore-auto-dns yes
nmcli conn modify "System eth0" ipv4.dns "192.168.24.7 8.8.8.8"
systemctl restart NetworkManager
Below that are the commands I used to check the pre-and-post states.
[root@idm ~] nmcli conn show "System eth0" | grep dns:
connection.mdns: -1 (default)
ipv4.dns: 128.31.27.57,8.8.8.8
ipv4.ignore-auto-dns: no
ipv6.dns: --
ipv6.ignore-auto-dns: no
[root@idm ~] nmcli conn modify "System eth0" ipv4.ignore-auto-dns yes
[root@idm ~] nmcli conn modify "System eth0" ipv4.dns "192.168.24.7 8.8.8.8"
[root@idm ~] nmcli conn show "System eth0" | grep dns:
connection.mdns: -1 (default)
ipv4.dns: 192.168.24.7,8.8.8.8
ipv4.ignore-auto-dns: yes
ipv6.dns: --
ipv6.ignore-auto-dns: no
[root@idm ~]# systemctl restart NetworkManager
[root@idm ~]# cat /etc/resolv.conf
# Generated by NetworkManager
search demo.redhatfsi.com
nameserver 192.168.24.7
nameserver 8.8.8.8
