Why use Email Verification Services, or not.

a burst of email

You’ve used it several times for marketing in the past.  Recently you used it again.  Some of your email messages came back because the addresses are invalid.  You want to send out another campaign but there’s only so much time you have to compose new content and get out a mailing.  Having over 29% invalid email addresses is so disappointing.   You do not have time for sanity checks; After all how many people leave out the @com on their Gmail address, or forget about that little dot between it.  Besides, this is an older list, and you believe all those addresses worked before?  Instead of deleting all those bounces, 29% of them.:

Does it make sense to trust an email verification service?

If you think about it, your member list, ideally, collected by you, is comprised of subscribers who are opted into your list.  All those addresses should be deliverable.  Why then would you use an email verification service which is only used to identify deliverable email addresses?   Could they help with those 29% bounced emails?

Just how is an email authenticated deliverable?

Letters with the word authenication

When an email is sent,  it’s essentially asking if a mailbox exists.  The sender’s server called the “Mail Transfer Agent” or MTA, searches the @domain.com portion of the recipients’ email address to determine the destination mail server. That server is known as the MX server (“Mail Exchanger”).  The MX server replies the email address is active or not.  (exists or not).  When you send several, hundreds, or thousands of emails for verification, each one is processed in succession.  In other words, once the MX server replies to the first request, it moves on to the next address

This process, checking a mailbox existence, was and still is widely used by Spammers.  When Dundee Internet began, Spam was virtually unknown.  Then around the late 1990s and early 2000s we became aware of dictionary attacks

A dictionary attack, a well-known spammer technique is used to validate email addresses.  It works by saturating a mail server with usernames from a dictionary type list, hence the name dictionary attack.  Accounts such as info@, president@, sales@ and so forth are usually the primary target.  This was an inexpensive way to verify a valid email box while creating a list of validated addresses.  ISPs, being the resourceful bunch we are, developed mechanisms to curtail these attacks, the easiest one being, to set the MTA to reject emails from unknown users.

Today, instead of using dictionary attack methods to valid email addresses, a spammer can hire an email verification service to achieve the same results – They eliminate, non-existent email boxes.  By elimination the result is a list of deliverable addresses.  But that’s all you get, email addresses, nothing more.  And by chance, someone on your validated list accepts your email (read or not). You may be surprised when suddenly, you’re on a  blacklisted.  Circumstances change:

Inactive email address, if they remain inactive, can become spam traps, or eventually deleted and recycled.  Someone else may create an ellen23982 or a barry995.   An email verification service will only verify these addresses are active, not the person associated with them.  

Email marketers should have, not only the email address of their subscriber, but the name attached to it. They may use several methods when collecting names and addresses, including, point of sale sign up, trade show collection, online sales, and website signup.  Regardless of how these addresses are gathered, it usually takes time to build up a good list of opted-in members.   During this process, mistakes will be made.  Addresses will be entered incorrectly, by accident or on purpose, depending on the collection method. The email marketer will know how to correct some of these errors by reviewing the bounce report.

A bounce report covers different types of bounces, and like everything else the nature of the bounce is in the details.


In this case, the part of the bounce report to pay attention to is the area that attributes a bounce to a non-existent email address, user or mailbox: these addresses need to be removed.   Other bounces may clear themselves up,  you can read more about bounces here.  


cartoon of a cell phone and envelope with a caption update your contacts

Email verification is not accurate, it only verifies that there is an active email address, not the name s behind it.  Just because delivery is good, the data (the email address owner’s name) doesn’t have to be.

The best way to verify an email address, collect addresses with data authentication, such as their name.   When you add those addresses, do some sanity checks, add the missing @ or dot com.  If they bounce as invalids, remove them from your list and move on.