Why you should avoid SMTP Email Address Validation
If you have a large number of email addresses in your database, you may be tempted to do SMTP validation to ensure that the email addresses are valid, before you mass email to them. There are, however, a few reasons why doing this is not a good idea.
In the past, mail servers would automatically validate email addresses. This was accomplished through the use of a simple SMTP command VRFY. This command would find out from the receiving mail server whether an email address was valid or not. This command, however, became abused by spammers on a large scale. For this reason, you will hardly ever see this command in use today.
Since the VRFY command is no longer an option, people have sought out an alternative way to verify email addresses. The way this method works is that a simulated connection to a mail server is created to mimic the sending of an actual message. This lets you know whether or not the email address is working. This method is commonly known as “SMTP email address validation”.
SMTP email address validation can be performed using a variety of applications and shareware programs. Why should you avoid doing this?
You Could End Up on a Blacklist
Doing this on a regular basis is likely to get you blacklisted sooner or later, especially your IP address. Internet service providers often share blacklists with each other, so you could find yourself on multiple blacklists. Onece you get on such a list, it’s difficult to get off them, regardless of how good your intentions are.
You Can Get Into Trouble With Your Own ISP
Even worse than getting blacklisted is getting blocked or terminated by your own ISP. While most customers don’t read the fine print of their ISP, the terms usually prohibit using an SMTP validator application. The reason for this is that such applications are usually associated with spamming. As with blacklists, it can be a long and arduous process to convince your ISP that you aren’t doing anything wrong once they’ve identified what they consider to be problem behavior.
It’s Not Always Reliable
Aside from the trouble you can get into, SMTP address validation is far from perfect. If, for example, someone is using a hosting platform such as Google Apps, they can easily set it up to forward email addresses that are not recognized as valid. Any mail server that uses a “catch all” function for inbound messages will cause address validation to be unreliable. This is an issue not only with Google Apps, but with many popular email hosting platforms. Thus, verifying email this way is not only dangerous, it’s not always accurate.
There, we have shared a few main reasons why it’s best to avoid email address validation through SMTP servers. It’s often inaccurate and, more importantly, it can get you labeled as a spammer!
Furthermore, email address validation like this is most likely prohibited by your ISP and will be looked upon with suspicion by other ISPs as well. The problems that this can cause outweigh any advantages.