How important is it for reverse DNS to match SMTP banner for email deliverability?
Summary
What email marketers say11Marketer opinions
Email marketer from SparkPost explains that Reverse DNS (rDNS) is important because it helps to verify that the IP address sending the email is authorized to send email for the domain it claims to represent. A matching rDNS record builds trust with receiving mail servers and improves email deliverability.
Email marketer from Mailjet shares that a reverse DNS lookup is a query to determine the domain name associated with an IP address. It helps email servers verify the authenticity of incoming emails. If the reverse DNS record doesn't match the sending domain, it can negatively impact deliverability.
Email marketer from Webmaster StackExchange shares that a lot of mail servers, especially larger ones, will reject mail if reverse DNS is not properly configured. This is one of the many basic checks that can improve email deliverability
Email marketer from Email Geeks responds that aligning reverse DNS and the SMTP banner is trivial and doesn't cost anything extra, questioning why someone wouldn't do it.
Email marketer from StackOverflow notes that a mismatch between the HELO/EHLO and the rDNS can raise red flags, even if it doesn't guarantee that the email will be marked as spam. It's best practice to ensure they align.
Email marketer from EmailAcademy explains that reverse DNS helps to verify that the mail server has been authorized to send emails, especially for a specific IP address. It is essential for building trust and credibility with ISPs, thus reducing the likelihood of messages landing in the spam folder.
Email marketer from SendPulse says that a Reverse DNS record helps to verify that a mail server is authorized to send emails using a specific IP address. This can significantly improve email deliverability by building trust with receiving mail servers and reducing the chances of being marked as spam.
Email marketer from MXroute Forums suggests that while a mismatch isn't always a deal-breaker, it is still a good idea to ensure the HELO/rDNS match as mail providers are getting stricter.
Email marketer from Email Geeks responds to reach out to Hubspot. If HubSpot provides a dedicated sending domain or IP address, ensure the PTR record for that IP address points to a hostname that matches the SMTP banner.
Email marketer from Reddit explains that having a proper rDNS setup is crucial for deliverability. It's like having a return address on a physical letter; without it, your email is more likely to be treated as spam.
Email marketer from GlockApps explains that ensuring your PTR record matches your SMTP banner is a basic step to improve your email deliverability. It helps to establish trust with receiving mail servers and reduces the likelihood of your emails being marked as spam.
What the experts say5Expert opinions
Expert from Email Geeks explains that unless they are confused, reverse DNS matching SMTP banner only applies to inbound mail. While not a big deal, it's a sign the mail server may not know its hostname.
Expert from Email Geeks explains that for deliverability, sender server configuration and DNS are key. A matching hostname in HELO and DNS is a good sign. While a mismatch won't break anything, aligning them looks more competent and professional.
Expert from SpamResource states that a reverse DNS lookup is an attempt to verify that an IP address is associated with a legitimate domain name. This is more important than ever since spammers rarely bother setting them up properly, so it is easy to filter based upon this criteria.
Expert Laura Atkins from Word to the Wise shares that having a HELO or EHLO that matches the reverse DNS/PTR record makes sure that the mail admins can find out who’s responsible for the mail stream and have some trust when the mail comes through.
Expert from SpamResource emphasizes that having correct and properly configured reverse DNS is one of the cornerstones of a good IP/domain reputation. It is a must to get email delivered.
What the documentation says4Technical articles
Documentation from Microsoft Docs shares that having a matching PTR record for your mail server's IP address pointing to your domain is important for verifying the legitimacy of your outbound emails. It helps in building trust and improves deliverability rates, as it confirms that the server is authorized to send emails on behalf of the domain.
Documentation from Google Workspace Admin Help explains that setting up a valid PTR record that matches the sending IP address to your domain is crucial. A mismatch can cause email to be marked as spam.
Documentation from cPanel explains that creating a PTR record that corresponds to your server's hostname can improve email deliverability. This helps to ensure that your emails are not flagged as spam by recipient mail servers.
Documentation from RFC Editor explains that SMTP servers MUST, in the EHLO or HELO command, send a domain name that either resolves to an address record, or is a valid literal address, as defined in Section 4.1.3. While not explicitly stating the importance of matching the reverse DNS, it does lay the groundwork for the need for a valid hostname.