Azure Virtual Networks - Supplying a non-existant DNS server

Question

I am busy creating a Virtual Network so that my Azure VMs can communicate with each other.

I'm currently on the screen (screen shot below) where I need to specify a DNS Server address. At this point I am unsure whether I will want to maintain a DNS server for name resolution or if I will just specify IP addresses.

Questions:

• What is the harm is supplying a DNS Server address here which may not exist?

• Does this mean that I could implement a DNS server at a later stage using the IP Address supplied on the screen below?

Thanks

Answer 1

Once a virtual network is created, you can only add subnets, and cannot change the DNS server without deleting the virtual network. So, if you want to keep the virtual network, make sure that you put in some DNS server addresses. You may want two. One for your private IP addresses (the VMs that you spin up in Azure) and one for public IP addresses. You should consider at least adding the public address DNS. I used the Google one on 8.8.8.8. You should use named addresses instead of IP addresses, but if you only have a few servers where it is not a big problem while you are still getting going.

It depends on if you are using a VPN gateway or if this is an Azure-only network, and if you are in dev/test versus production. If you are in production, deleting the virtual network can cause significant downtime. If you have a VPN gateway, making frequent changes on the 'other end' may be more difficult.

Answer 2

Now you can leave the DNS Server blank when creating a Virtual Network and update it later.