MX records tell the internet which servers are responsible for receiving email for a domain.
That makes MX validation one of the most useful technical checks in email review.
Why it matters
If a domain has no usable MX setup, email delivery is much harder to trust. That does not tell you everything about the specific mailbox, but it does tell you something important about the destination domain.
What MX validation helps catch
- domains that are not properly set up for mail
- obvious domain-level delivery problems
- addresses that look fine on the surface but point somewhere unusable
What MX validation does not tell you
It does not prove that a specific mailbox exists.
That is why it should be treated as an important signal, not the only signal.
Where MailCull uses it
MailCull includes domain and MX validation as part of its standard checks in both Verify List and Verify Email.
That helps separate a merely well-formed address from one whose domain also appears ready to receive mail.