Do PTR records and HELOs impact email deliverability?
Summary
What email marketers say11Marketer opinions
Email marketer from Stack Overflow suggests that the HELO setting should match your server's fully qualified domain name (FQDN). If it doesn't, some mail servers might reject your emails, especially those with stricter security policies.
Email marketer from SendGrid suggests that PTR records are essential for reverse DNS lookups, and they help verify that the sending IP address is associated with a legitimate domain. A valid PTR record can improve email deliverability by assuring receiving servers that the sender is not a spammer.
Email marketer from Neil Patel's Blog shares that PTR records are critical for establishing trust and verifying the sender's identity. A properly configured PTR record can significantly improve email deliverability rates by preventing emails from being flagged as spam.
Email marketer from Email Geeks recommends that the PTR should be a subdomain of your sender domain to improve deliverability on Hotmail and iCloud, reducing the domains spam filters need to check.
Email marketer from Email Geeks explains the reason to change PTRs and HELOs is to lower the amount of different data points in the email, as a HELO from an ESP domain with poor reputation can impact the email. He notes this isn't always an issue.
Email marketer from Gmass shares that a PTR record is crucial because email providers use it to verify that the IP address of the mail server matches the domain name specified in the email's headers. A mismatch can lead to emails being flagged as spam or rejected outright, so it's essential to have a correctly configured PTR record.
Email marketer from Reddit explains that not having a PTR record is like driving a car with no license plate. Some servers might not even accept your emails, and many will mark you down as suspicious. It's a basic hygiene factor that is crucial to implement.
Email marketer from Litmus explains that while authentication methods like SPF, DKIM and DMARC are vital, ensuring your servers are correctly configured with valid PTR records and HELO/EHLO greetings matching your sending domain enhances your sending reputation and therefore improves deliverability.
Email marketer from SparkPost shares that proper email infrastructure setup, including PTR records and consistent HELO/EHLO greetings, is essential for building a good sender reputation. They advise that ensuring these elements are correctly configured can significantly improve inbox placement rates.
Email marketer from MailerQ shares that PTR records ensure the server resolves to a domain name and helps build trust with receiving mail servers. If the rDNS isn't properly set, your server may appear illegitimate, leading to lower deliverability rates.
Email marketer from Mailjet explains that the HELO/EHLO greeting is a key part of the SMTP handshake. They say that it is crucial the domain presented is valid and has a good reputation. A mismatch or a poorly regarded HELO/EHLO domain can damage sender reputation and deliverability.
What the experts say4Expert opinions
Expert from Word to the Wise Laura Atkins answers that using a generic HELO/EHLO domain from ESPs can cause filtering problems, especially if the ESP’s IPs are used for sending spam, making it difficult to differentiate legitimate senders from malicious ones. Using a dedicated IP or ensuring that the HELO/EHLO is properly configured can improve deliverability.
Expert from Spam Resource explains that the HELO/EHLO string should be a valid, fully-qualified domain name (FQDN) that resolves to the sending server's IP address. They add that using generic or non-resolvable HELO/EHLO strings can negatively impact deliverability as it appears suspicious to receiving mail servers.
Expert from Spam Resource shares that PTR records are crucial for reverse DNS lookups, which help verify the authenticity of the sending server. A missing or incorrect PTR record can negatively affect email deliverability as it makes it difficult for receiving servers to confirm the sender's legitimacy.
Expert from Email Geeks shares that PTR shouldn’t really matter for deliverability, using Google as an example. However, some smaller ISPs might be picky if the sending IP PTR domain doesn't match the sending domain.
What the documentation says4Technical articles
Documentation from Microsoft Learn explains that a PTR record (reverse DNS lookup) maps an IP address to a domain name, and it is crucial for verifying the identity of the sending server. A mismatch or missing PTR record can negatively impact email deliverability, as it may cause the receiving mail server to flag the email as spam.
Documentation from RFC 5321 states that the HELO or EHLO command identifies the SMTP client to the SMTP server. The domain specified in HELO/EHLO should be a valid, resolvable domain name associated with the sending server. An improperly configured or missing HELO/EHLO can raise suspicion and harm deliverability.
Documentation from DigitalOcean Community explains how to set up a PTR record. They share that it’s essential for reverse DNS lookups, allowing mail servers to verify the legitimacy of your server and prevent your emails from being marked as spam.
Documentation from Google Workspace Admin Help explains that maintaining consistent and accurate DNS records, including PTR and forward DNS records, is essential for email deliverability. Specifically, the HELO/EHLO should match the sending server's hostname, and the hostname should resolve correctly to the IP address via DNS. This helps build trust with receiving mail servers.