Your DNS and Web server on the same white ip?

Question

linux

There is a domain that will redirect requests to a dedicated server, there is a dedicated server with one white ip. You need to raise your web server on it and raise your dns server (don't ask why, it's necessary, hosters' dns disappear).
I want to do like this:

1. The host machine will be a Linux server based on Debian 10
   
2. I want to set up a kvm-based virtual machine on it
   
3. First virtual dns server
   
4. The second virtualka web-server
   

since there is only one ip, I want to raise the network in kvm to nat. I am not strong in dns and after reading a few manuals, I realized that I need to install an authoritative dns server and here I have a few questions for experts:

1. Will just one ip be enough for me for dns and for a web server? (i.e. I will filter dns traffic to the dns virtual machine, and web traffic to the web virtual server through the host machine)
   
2. Can I not install a second dns server?
   
3. If you still need a second dns server, will just one ip address be enough for me?
   
4. I heard that kvm in nat mode is buggy on the network, is it so?
   

If there is an experience of this kind, describe it.

Answer 1

1.4. One address is enough. Virtualization is not needed. Both roles can be deployed on the same server.
2.3. You can, but you shouldn't. Whether you can deploy it on one server depends on the domain registrar, if he doesn’t give a damn and allows you to delegate to one server with one or two addresses and different names, then it worked. The secondary DNS service is not that expensive, and IMHO it's not worth it to make crutches and reduce DNS availability in case of problems on the server or hoster.
There is an experience of this kind, but laziness does not need to be encouraged - so you will not wait for step-by-step instructions. Read the docs, google or look for a specialist.

Answer 2

Another IP address may be required. Not every registrar allows you to specify NS servers on the same IP.

Answer 3

I want to set up a kvm-based virtual machine on it.
The first virtual machine is the dns server
. The second virtual machine is web-server.

What for? To isolate services? If there is no serious reason to fence such towns - deploy everything on the host linux, bind and apache / nginx will get along fine

Can I not install a second dns server?

The registrar may not register the necessary records without the presence of secondary DNS. The secondary zone at the registrar usually costs a penny

Answer 4

You have made something up in terms of the structure of the organization of services, or you have not correctly raised the question of why virtual machines are required for this. Both DNS and Web server and much more can be organized on one white IP and one VDS, without any additions. If the final you do not plan for some reason isolation.
For a full-fledged DNS server, you really need 2 DNS slaves on which your zone will be duplicated - a classic of the genre!