Email Validation

Comprehensive email validation. Check to see if the email address actually exists

3 steps to full email validation

Step 1 is very rudimentary and is essentially syntax checking. All this does is ensure that what you enter looks like an email address (before I go making unnecessary calls to whois and DNS servers).

Step 2 is to ensure that the domain name exists and checking for MX or A entries in the DNS. This will mean you can be fairly sure that a mailserver exists that expects to recieve email at that domain.

Step 3 Using the SMTP protocol we contact the domain mailserver to ask if the user is valid. This is almost a guarantee that the mailbox exists, however there are several exceptions to this rule (including domains with a catch-all mailbox).