Azure DNS Server 168.63.129.16 and RHEL NetworkManager

When I created a private DNS zone in Azure, I assumed I would also need to set up a DNS server inside the private network to handle name resolution — but it turns out 168.63.129.16 is already operating as a DNS server.

https://learn.microsoft.com/ja-jp/azure/virtual-network/what-is-ip-address-168-63-129-16

In other words, by adding the following to /etc/resolv.conf:

nameserver 168.63.129.16

name resolution will work based on the A records registered in the private DNS zone.

On RHEL and similar systems, NetworkManager automatically finds the optimal DNS server (i.e., 168.63.129.16) and registers it in resolv.conf.

Conversely, if you want to configure resolv.conf yourself, you can prevent NetworkManager from overwriting it with the following configuration:

$ cat /etc/NetworkManager/conf.d/90-dns-none.conf [main] dns=none

$ sudo systemctl restart NetworkManager

That's all.