There are a lot of them out there...

I get a lot of feedback from "sdsd" at email address "asdsd".

He also signs up to my newsletter several times a day.

He sends "Tell-a-friend" emails to his pals at "dsadd" fairly regularly.

If you provide any sort of email functionality on your site he'll visit your site too!

Step 1: Simple validation

There are many articles, from very simple to extremely complex, that show you how to make sure email addresses are valid. Remember that they are all just guessing.

Simple validation basically checks that there's one "@" and one ".". In extreme cases some even check for malformed IP addresses! This level of validation is called "syntax checking".

This page, and my email validation service, is powered by the top two leading validation components, Hexillion and ASPNetEmail.

Of course, our friends at "sdsds" will fail simple validation, so there are uses for this level of validation. But (and it's a big butt) in my experience there are many people who are more than willing to go the extra mile and enter "sdasd@asdasd.com" just for grins and giggles.

Let's try it. Enter an email address below. See how easy it is to fool!

Step 2: DNS validation

The first real step is to make sure that the domain actually exists. Finding an MX or A entry in the Domain Name System, or DNS, means that you're pretty sure that there's a mail server there eagerly awaiting your emails. This is a huge step towards ensuring the email address is valid!

Let's try the DNS validation. Enter an email address below - you should find this significantly harder to fool!

Step 3: SMTP validation

The DNS check will probably be enough in most cases - after all, if the domain exists that's more than half the battle. Typo's will be caught, and most jokers will give up at that.

However, "asdfqad@mindspring.com" will still be let through, regardless of whether it was mis-spelled or entered deliberately.

I still have one method left though, and this all but guarantees that the email is perfect. This method uses the SMTP protocol to contact the domain mailserver and actually ask if the user is valid!

A few small caveats - some mailservers don't effectively support this feature, and other domains have a "catch-all" email address so all mail is accepted. Of course the latter isn't really wrong since the whole point was to stop email being bounced.

Let's try the full blown test. Enter an email address below, and be patient - it can take awhile!

That's it! Whatever email validation method you want to use, from the <1 millisecond syntax check to the "up to 70 seconds" SMTP validation, there's a method here for you. Just think of all that junk mail you'll save yourself...