Email Validation to Improve Deliverability

How can you decide if an email address has a valid opted-in address or not?
It is imperative for your reputation that you do not spam! Protecting your sending
reputation helps your valid email addresses get delivered and keeps you off the
blacklist of spam filters. It is very important to remember that emailing to addresses
that did not opt-in is a major cause of delivery issues. Delivery issues can occur
on the list itself or based on other users of the same server. Thus, the validation
process should be followed by all users of that server’s email marketing platform.

The following is a description of a simple process for validating your email list.

Each part of an email address is inspected as it goes through a validation process.

These parts are as follows:

  • oLocal Part – the part of the email address before the @ is inspected. Example
    Jsmith of
  • oDomain Part – the part of the email address after the @ is inspected.
  • Example of
  • oEntire Address – the entire email address is inspected.
  • Example


Inspecting the Local Part

The local part of an email address is inspected for a match from one of the local
parts listed below. If the local part of the email address is listed below, then
the email is considered invalid.

Here are the local parts that should never be emailed:

biz devinvestorpostmaster


Again, these local part should never be on a list that is opted-in,
as they are either spam traps or they are for administrative purposes only. Basically
an email address that belongs to a group of people and not an individual can be
seen as spamming as one person cannot opt out.


Inspecting the Domain Part

Some of domains that should never be emailed are listed below. Each one used to
be a valid domain, but are no longer considered valid. Thus, an email address with
one of these domains is invalid and probably has been invalid for at least 5 years.

Here are some domains that should never be emailed:



Again, these domains should never be on a list that is opted-in; these domains
should never be sent an email, as they have been invalid for over 5 years.

In addition to spam filters inspecting the domain part of an email address for
domains like those above, the spam filters checks to see if a valid MX record for
the domain exists.


What is an MX record?

Wikipedia, a mail exchanger record (MX Record) is a type of resource record
in the Domain Name System that specifies a mail server responsible for accepting
email messages on behalf of a recipient’s domain.

If an MX record does not exist for a domain part, then that email address is invalid
and should not be sent to. Most invalid email addresses are invalid because of
no MX record due to the misspelling of the domain. There would be no valid MX Record
for or yahoo.coom, for example.


By making sure your email marketing program uses validation, you can make sure
your reputation is kept clean and your emails have a better chance of being delivered.

Next blog article will cover validating the full email address and some other
steps in the process.