Validation of Email Addresses for Protection Against Spam Bots on the Website

E-mail is still one of the most important and effective elements of online business and marketing and is the most effective channel for generating revenue. Therefore, for any online business and website owners, it is important to be sure that the email owner used it for registration/subscription so that the user used his real email address.

There are several important reasons for this.

First, it is important to recover the forgotten password, for example: the user has misspelled his email address, after a while used the password recovery function and cannot get a new password.

Second, this user will not receive your email notifications.

Third, the user whose email was used by spammer for registration/subscription will send your newsletter to spam. Further, spammers can use this email for sending spam, brute force, etc.

The use of such emails for marketing mailings and other mailings may carry certain risks for the owner of the site and increase the risks of adding to the lists DNSBL, various blacklist’s, increase the likelihood of getting into the spam folder and your other emails. Increase your budget costs for mailing to fake addresses or addresses whose owners have been compromised by spammers.

To avoid or minimize risks to a minimum, the list of email addresses must be checked before sending.

Recently, we started checking the existence of email addresses, which checks if such an email address exists or not. It uses the MX records of the domain of the email address and connects to the mail servers (via SMTP, and also simulates the sending of the message) to ensure that the mailbox does exist for that user/address and it can receive mail.

This test solves several tasks at once, reducing the likelihood of skipping spam and allowing users to check the emails of their users. To test users, you can use the API method https://cleantalk.org/help/api-spam-check.

An example of the result of the API response for https://cleantalk.org/blacklists?record=mattressfg%40gmail.com

{"data":
            {"mattressfg@gmail.com":
                      {"appears":1,
                      "frequency_time_10m":0,
                      "spam_rate":"1",
                      "frequency":"8",
                      "frequency_time_24h":1,
                      "updated":"2018-03-26 00:26:48",
                                                  "exists": 0, 
                      "frequency_time_1h":1}
            }
}

At the moment, we use this tool only to improve spam detection and check all email addresses that have had spam activity in the last 10 minutes. For checked addresses, a flag is set in the database, which is taken into account in the further spam filtering and API response.

“exists”: “1” – exists

“exists”: “0” – does not exist

You can sum up the interim results; the percentage of non-existent email addresses in the spam mailing is 25.34%.

We collect information about spam IP/email addresses from more than 237,000 websites. The email database contains more than 10,095,239 email addresses. And in our immediate plans, check all emails in the database and run a scan of all the email addresses that are processed by the service.