How would you recommend assigning technical and mail subdomains for a linux server?

Question

linux

there is a main domain. On it, subdomains are sites. When installing a debian or ubuntu server, /etc/hosts must be set to the correct domain name. Also, when installing other software, you need to specify the mail domain. What is more correct to indicate?

Suppose we own the administrator.ru domain,

what should be specified in hosts as a technical domain and what should be specified as a mail domain when installing the main packages requiring this?

tech.administrator.ru
mail.administrator.ru

or what is more correct?

in hosts what should be specified more correctly?

Answer 1

It seems to me - no matter what name to ask. If only it was written in the forward and reverse DNS in the same way.
(The reverse record can be set by the provider - then it can be ignored.)
About " other software " - you need to look at why he asks for a mail domain. I think - it is necessary to specify any to which letters correctly come.

Answer 2

Anything. There are no rules governing this. The mail server is usually called mail (or mx), the DNS server is ns, the proxy is suddenly proxy, the VPN server is vpn, but these are just common names and no one will tell you anything if you call the server, for example, the names of Shrek characters :)

Answer 3

Regardless, it will be correct to specify administrator.ru as the mail domain.
Since your mail is corporate and it’s better to have this look
[email protected]
than
[email protected]
just don’t forget that the MX record and not A is responsible for the mail server,
and therefore, even with the same domain, they can be located in different places.
As for servers
, there is a little confusion here and is related to AD where a domain name is also used.
And here I would really already do the divisions, but that's another story.
The server can specify its host as the main site lying on it and also specify it in NS servers as the main one.
BUT here you really need to look at your topology.
For example, if you have a VPS server, then it would be logical to call them, say
VPS1.administrator.ru
VPS2.administrator.ru
mai.administrator.ru
, etc. if they are separate and isolated, moreover, I’ll note the administrator.ru DNS zone
should be kept somewhere in cloud, because when 1 server with a DNS server crashes, the rest will also fall.
In short, it will be right to do as it is more convenient for you, there is no standard.
But you need to look at your topology to accurately recommend