Is it a good idea to verify email addresses by connecting to servers?

Email marketer from Hunter.io suggests that while email verification tools can be helpful, directly connecting to servers for validation can be problematic. They advocate using their own email verification system.

Email marketer from ZeroBounce explains that using SMTP verification to validate emails directly has become less reliable. Many servers now intentionally obscure the status of invalid addresses to prevent harvesting. It is better to look at using more modern validation methods.

Email marketer from LinkedIn suggests that SMTP verification carries the same impact as sending a message. Therefore, there is an associated risk. They recommend using specialist tools.

Email marketer from Email Marketing Tips suggests that email marketers should carry out a test send to see how their list behaves before blasting out a campaign to everyone. They suggest using a few valid test emails and see what happens, and reviewing the bounce list.

Email marketer from NeverBounce explains that directly querying mail servers to validate email addresses is risky due to its potential impact on sender reputation and unreliable results. Most mail servers now employ greylisting and other techniques that impact SMTP probing.

Email marketer from Email Hippo explains that many techniques are used to verify emails including syntax checking, domain verification, and mailbox verification. However, techniques like SMTP probing are less favoured due to privacy and accuracy issues.

Email marketer from Reddit explains that attempting to verify email addresses by directly connecting to mail servers can be seen as aggressive and can hurt your sender reputation with ISPs. Using 3rd party verification tools are a good option.

Marketer from Email Geeks warns that some of these companies have a double sided business where they package up your list and sell them as "fresh" contacts.

Email marketer from Mailjet explains that directly connecting to servers to verify email addresses, while seemingly efficient, can damage your sender reputation and lead to blacklisting. This approach mimics spammer tactics and can trigger security measures.

Email marketer from StackOverflow suggests that attempting SMTP verification is technically complex and unreliable, and can flag you as a potential spammer. Implement SPF, DKIM, and DMARC

Expert from Word to the Wise Staff explains that email list scrubbing tools carry privacy risks and should be fully checked. They may harvest and resell your list.

Expert from Email Geeks warns that there’s at least one snowshoe spammer who is also selling a data hygiene service and that he sends his spam out to your list and then tells you what addresses bounced.

Expert from Email Geeks adds that if you use a crappy service to check email validity, it'll get blocked. Then it'll think your email addresses don't exist, and they'll tell you to throw away good addresses.

Expert from Email Geeks explains that checking the validity of email addresses this way has been done for 2 decades and hitting too many bad email addresses hurts your reputation because of it. Many smarter verification companies don't do this anymore because it is near impossible to actually do it and not get blocked. It’s abusive and wrong. The reason there are 3rd party companies that do it is because it trashes your reputation. And many of them were forced to do spammer level tactics in order to not get blocked - moving IPs, changing domains on a regular basis, hiding their identity… all the things spammers do.

Expert from Word to the Wise (Laura Atkins) explains that address verification systems carry many risks and disadvantages including false-positives. They can also harvest your list and resell it to others.

Documentation from Auth0 recommends multi-factor authentication as a more robust means of ensuring good email validity. They recommend sending a confirmation email to ensure the user does own the email address.

Documentation from Microsoft explains that practices like list bombing will impact your email reputation. They recommend implementing measures to prevent bounce backs and invalid emails.

Documentation from Twilio SendGrid covers techniques to maintain a good sender reputation. These include managing subscription preferences, preference centers, and segmentation lists. Also covers bounce management. They do not recommend SMTP verification.

Documentation from Amazon Web Services explains that Amazon SES recommends using methods like double opt-in and suppression lists instead of directly querying mail servers. Using outdated or incorrect email lists can hurt your sender reputation. They recommend utilizing their own email validation service instead.

Documentation from RFC Editor explains that while SMTP theoretically allows for verifying the existence of a mailbox via the VRFY command, its use is often disabled or unreliable due to security concerns and the potential for abuse. Attempting to verify addresses in this manner is generally discouraged.