Summary
Reverse DNS (rDNS) is a crucial element in email deliverability. It acts as a means of verification, enabling receiving mail servers to confirm the identity of the sending server by ensuring that the IP address is associated with the domain it claims to be. This verification process helps establish trust and improves the sender's reputation. A missing, incorrect, or generic rDNS record is a red flag that can lead to emails being flagged as spam or rejected. Proper configuration, including forward confirmation (HELO/EHLO matching DNS), is essential for legitimate senders to maintain good deliverability and avoid spam filters. rDNS serves as a first line of defense against spam, and a valid PTR record pointing back to the hostname of the mail server is important.
Key findings
- Identity Verification: rDNS allows receiving mail servers to verify the identity of the sending server.
- Spam Prevention: A missing or incorrect rDNS record is a red flag that increases the likelihood of emails being flagged as spam.
- Sender Reputation: A properly configured rDNS is crucial for improving sender reputation, which directly impacts deliverability.
- Generic rDNS Issues: Generic rDNS records or a lack of clear sender identification can negatively impact deliverability.
- Importance of PTR Records: A matching PTR record pointing back to the hostname of the mail server is vital.
- First Line of Defense: rDNS acts as a first line of defense against spam and unverified senders
Key considerations
- Valid rDNS Record: Ensure the domain has a valid rDNS record that matches the sending IP address.
- Avoid Generic rDNS: Ensure the rDNS record is not generic and clearly identifies the sender.
- Forward Confirmation: Verify that forward confirmation (HELO/EHLO matching DNS) is correctly configured.
- PTR Record Setup: Ensure the IP Address has a matching PTR record pointing back to the hostname of the mail server.
- Proper Configuration: Maintain a properly configured reverse address mapping to ensure the server is who it says it is.
- Regular Review: Periodically review rDNS records and settings to ensure accuracy and prevent deliverability problems.
What email marketers say
7 marketer opinions
Reverse DNS (rDNS) is crucial for email deliverability because it helps establish the legitimacy of the email server. It allows receiving servers to verify that the IP address is associated with the domain it claims to be, building trust and improving sender reputation. A missing, mismatched, or generic rDNS record is a red flag that can lead to emails being flagged as spam or rejected by receiving servers. Ensuring a valid rDNS that reflects the brand or organization is essential for avoiding spam filters and maintaining good deliverability.
Key opinions
- Legitimacy: rDNS helps establish the legitimacy of the email server by confirming the association between the IP address and domain.
- Sender Reputation: A properly configured rDNS is crucial for improving sender reputation, which directly impacts deliverability.
- Spam Flagging: Missing, mismatched, or generic rDNS records can lead to emails being flagged as spam by receiving servers.
- Verification: Many ISPs and spam filters use rDNS as a primary method to verify the legitimacy of a sending server.
- First Line of Defense: Reverse DNS serves as a first line of defense against spam.
Key considerations
- Valid rDNS: Ensure that the rDNS record is valid and reflects the brand or organization, not the default pattern assigned by the hosting provider.
- Matching rDNS: The rDNS should match the sending domain to avoid being flagged as spam.
- Monitor Reputation: Continuously monitor sender reputation to ensure that deliverability is not negatively impacted by rDNS issues.
- PTR Record: Ensure the IP Address has a matching PTR record pointing back to the hostname of the mail server.
- Forward Confirmation: Having correct forward and reverse DNS records can help with deliverability.
Marketer view
Email marketer from Email Geeks explains that this pattern would lead to an increased chance of being marked as spammy based on sending IP at Cloudmark. Recommends legitimate senders to ensure a suitable valid rDNS set that reflects their brand or organisation and is not the default pattern that the hosting provider assigns.
4 Sep 2022 - Email Geeks
Marketer view
Email marketer from Reddit User Throws_Up_Sunshine shares that having a proper rDNS record is absolutely crucial for good deliverability. Many ISPs and spam filters use it as a primary way to verify the legitimacy of a sending server. If your rDNS doesn't match your sending domain, your emails are likely to end up in the spam folder.
14 Feb 2022 - Reddit
What the experts say
4 expert opinions
Reverse DNS (rDNS) is crucial for confirming the identity of an email sender and improving deliverability. A missing or incorrect rDNS record raises red flags and can lead to spam filtering. The rDNS should not appear generic and should clearly identify the sender. Correct forward and reverse DNS records, ensuring that HELO/EHLO matches DNS, are essential for establishing sender legitimacy.
Key opinions
- Sender Identification: rDNS helps receiving mail servers confirm the identity of the sending server.
- Deliverability Impact: Correct forward and reverse DNS records improve email deliverability.
- Generic rDNS: Generic rDNS or a lack of clear identification can negatively impact deliverability.
- Red Flag: A missing or incorrect rDNS record serves as a red flag for spam filters.
Key considerations
- Avoid Generic rDNS: Ensure that the rDNS record is not generic and clearly identifies the sender.
- Forward Confirmation: Verify that forward confirmation (HELO/EHLO matching DNS) is correctly configured.
- Correct rDNS: Implement and maintain correct and accurate rDNS records.
Expert view
Expert from Word to the Wise explains that having correct forward and reverse DNS records can help with deliverability. Forward Confirmation means that your HELO/EHLO matches what your DNS forwards to and having forward confirmation helps the mail server know that the sender is who they say they are.
8 Feb 2022 - Word to the Wise
Expert view
Expert from Email Geeks shares that the term for the issue is “generic reverse dns” rather than static vs dynamic, and sending mail from there is not recommended.
26 Jan 2022 - Email Geeks
What the documentation says
4 technical articles
Reverse DNS (rDNS) and PTR records are crucial for verifying sender identity and ensuring email deliverability. Email servers perform reverse DNS lookups to confirm the sender's authenticity. Without a valid rDNS record that matches the sending IP address, emails are more likely to be marked as spam or rejected. Properly configured reverse address mappings are essential for establishing trust and increasing the likelihood of successful email delivery.
Key findings
- Identity Verification: rDNS is used by email servers to verify the sender's identity.
- Spam Prevention: Lack of a valid rDNS record increases the likelihood of emails being marked as spam.
- Authorization Check: PTR records help verify that the sending server is authorized to send email for the domain.
- Trust Establishment: Creating an rDNS record helps establish trust with other mail servers.
- Standard Compliance: Every internet-reachable mail server should have a reverse address mapping.
Key considerations
- Valid rDNS Record: Ensure your domain has a reverse DNS record that matches the sending IP address.
- Proper Configuration: Configure reverse address mappings to ensure the server is who it says it is.
- Consistent Setup: Implement a reverse DNS record as an essential part of setting up an email server.
Technical article
Documentation from Microsoft Learn responds that a PTR record (reverse DNS) is important because some email systems use it to verify that the sending server is authorized to send email for the domain. Without a valid PTR record, your email might be rejected or marked as spam.
10 Aug 2021 - Microsoft Learn
Technical article
Documentation from Google Workspace Admin Help explains that reverse DNS is important because many email servers perform reverse DNS lookups to verify the sender's identity. If your domain doesn't have a reverse DNS record, or if the record doesn't match your sending IP address, your emails are more likely to be marked as spam.
19 Oct 2024 - Google Workspace Admin Help
How do I check if the sending IP address matches the IP address of the hostname specified in the Pointer (PTR) record?
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