I help a friend run a server, which includes a mail server. http://mxtoolbox.com reports that our reverse DNS is not a valid hostname.
The reverse DNS currently points to
domain.com. Should it point to
hostname.domain.com? I have seen here that it is conventional to use this scheme for reverse DNS. However, will this cause a problem if the mail server responds like this:
220 domain.com ESMTP Postfix (Ubuntu) EHLO PWS3.mxtoolbox.com 250-domain.com 250-PIPELINING 250-SIZE 10240000 ...
Basically, will the reverse DNS pointing to a subdomain of the domain the mail server reports be valid?
EDIT: My original question was as follows:
If the mail server reports
domain.com as its FQDN, can the reverse DNS point to
hostname.domain.com? See comments below for why this isn’t needed, and why both should be the same.