How to create the same ns for different servers?

Question

Domain Name System

Hello!
I can not understand. Help, who understands this.
There are several VPS from different hosts in different countries. I want that when you prescribe ns1.mydomain.com and ns2.mydomain.com for the domain, the site for which you specify these ns will be available, regardless of which of these VPS it is hosted on.
I can't figure out how to do it.
Created two identical A records and directed to different IPs (IP, where VPS) for ns1.mydomain.com and ns2.mydomain.com Like
this:
ns1.mydomain.com → 1.1.1.1
ns1.mydomain.com → 2.2.2.2
like everything works, but then there are problems with mail for the domain. Letters do not reach.
All VPS are powered by ISPmanager. One for version 4, one for version 5.
Maybe someone faced such a problem. I would appreciate any help or advice. Thank you.

Answer 1

shta?
1. does the site migrate between hosts?
2. 3 hosts for one site, or different ones?
3. do the hosts have a static ip?
4.ns yours? or third party?
5. if yours, is it hosted on one host, or is it duplicated on all 3 hosts?
6. Why do you need your ns?

Answer 2

DNS can't work that way. If you specify two addresses for the same name, both must be available at the same time. When resolving a name, the application gets the full list of addresses, but usually uses only one, and on a connection error, it assumes that the entire host is unreachable. You can make a virtual proxy on 3.3.3.3, which will monitor 1.1.1.1 and 2.2.2.2, and forward the request to the address that is currently working, and publish 3.3.3.3 in DNS.

Answer 3

DNS is just a worldwide distributed database of matching IPs and server names (well, some other information). It does not carry out any monitoring and does not redirect any requests anywhere. What you have done is called round-robin DNS, when DNS randomly redirects clients to the first server, then to the second - while both of them must be available at the same time .