These are the essential checks that are performed by each operation. The service operation steps through each section to determine if an email is valid. If one step fails, subsequent checks are not made because they have been logically eliminated. Example: if the syntax on an email fails, neither the DNS nor the SMTP check is done.
Steps
The email is first cleaned and corrected before being validated and verified. Extraneous text and characters are removed and common email deformities are fixed. Typos, misspellings as well as incomplete domains are also corrected.
The email is tested to verify that the format is valid, such as an "@" symbol, a domain, and no odd characters that aren't allowed in email addresses. The rules specific to the domain are also checked. For example, if you input aa@aol.com it will pass the syntax check but fail the domain specific syntax check, and therefore we do not need to continue with the DNS or SMTP level checks.
The DNS or domain name check verifies that the domain exists and has a valid MX record in order to relay mail.
Once we obtain the location of the mail server from a successful DNS check, we start communicating with the target mail server. No email is actually sent to the email address being verified. This step gives us three pieces of information. It tells us if the server is working, if it will accept any address, and if will it accept this specific address. One difficulty of email validation is dealing with the defensive behaviors of email servers. Because of the growth of spam and email-mining tools, SMTP servers often respond to requests for information in cryptic and defensive ways. Mail servers may respond very slowly to information requests, provide unhelpful data, or sometimes no data at all. We have carefully crafted our system with this in mind, and therefore the data we return is still very accurate. However, sometimes we are still forced to return an unknown result for some of the SMTP level checks.
A deliverable email address is not always a good email address. Just because an email does not bounce back does not mean that it was received, and so our service performs a variety tests and checks to evaluate the integrity of an email address. For example an email address may be a disposable address that is only temporarily deliverable or worst yet a spam trap.
