Mail on a 3rd level domain?

Question

linux

Hello! There is a domain.ru domain with mail (if it is important, on Postfix + Dovecot), addresses of the form [email protected]
It has the following DNS structure:

$TTL 30
$ORIGIN domain.ru.

@ IN SOA ns01.lanlinux.ru. root (
                2019062801 ;Serial
                1d ;Refresh
                1h ;Retry
                1w ;Expire
                2h ) ;Negative Cache TTL
;
@               IN      A       x.x.x.x
@               IN      NS      ns01.domain.ru.
@               IN      NS      ns02.domain.ru.
@               MX      5       mail.domain.ru.

ns01            IN      A       x.x.x.x
ns02            IN      A       x.x.x.x
mail            IN      A       x.x.x.x

It is necessary to carry out mailing from the address [email protected]
What changes are needed in the DNS? In theory, I can set up a new mail domain mail.photo.domain.ru on the same Postfix.

Answer 1

add
foto IN A xxxx
foto IN MX 5 mail.domain.ru.
in DNS and configure Postfix to process the domain foto.domain.ru

Answer 2

1. For some reason, it is missing ...
@ MX 10 domain.ru.
Well, okay))) the mail server probably works fine. Although 10 years ago such a record was required.
2. Almost the same as latush , but you can also use CNAME
foto IN CNAME mail.domain.ru. (there's a catch, read on)
foto IN MX 15 foto.domain.ru. I think it's better not to write mail.domain.ru here. The mail server looks for the MX record foto.domain.ru, not mail.domain.ru.
Well, set up a mail server to receive and send letters ... there may be problems if you do it on the same mail server. Like banging his head on the table. There was domain1.ru and domain2.ru and the infection was sent from the user [email protected] via domain1.ru. I don’t remember how I solved the problems ... it was a very long time ago)))
3.

Mail on a 3rd level domain

Do not even think ))). For a 3rd level domain, you need to register NS from the beginning, then set up the zone, create records like mail.photo.domain.ru. There are many dances with a tambourine)))

Answer 3

From the records of this complete scam will come out. Dmarc, dkim, sfp records, no? Do you even know how mail works? Maybe read the Russian Federation? It will fly into gray list and black list in a matter of days. If the user himself is not subscribed to this, you are even more expensive there, you have already suffered enough in zero spammers.
Sorry for the emotional feedback.
And ptr record at the provider? Successfully forgotten? Your mail will not work for long.