Summary
Reverse DNS (rDNS) failures from AT&T stem from a combination of factors, including temporary outages or misconfigurations within AT&T's network and incorrect or missing PTR records on the sender's side. These issues are widespread, with AT&T aware of the problem but an ETA for a fix uncertain. Proper rDNS configuration, involving valid PTR records matching the sending domain's hostname, is crucial for email authentication, gaining trust, and avoiding rejection as spam. Maintaining a good sending reputation is also vital. Resolution strategies involve monitoring AT&T's status, contacting their support, using diagnostic tools to verify PTR records, and potentially implementing workarounds like alternative sending IPs or throttling.
Key findings
- Multiple Root Causes: Causes include AT&T network issues and sender-side PTR record problems.
- Widespread Impact: The issue affects many users, indicating a systemic problem, not isolated incidents.
- rDNS is Key: Correct rDNS/PTR record configuration is essential for email authentication and trust.
- AT&T Aware: AT&T is aware, but the timeline for a resolution is not known.
- Beyond AT&T: Problems with rDNS records will cause issues sending email to any mail provider not just AT&T
Key considerations
- Monitor AT&T Status: Stay informed about AT&T network status and potential fixes.
- Check and Correct PTR: Ensure the sending IP has a valid PTR record matching the hostname used in HELO/EHLO.
- Contact AT&T Support: Report the issue to AT&T and request DNS record corrections.
- Sending Reputation Matters: Maintain a good sending reputation to minimize the impact of rDNS problems.
- Consider Workarounds: If necessary, use alternative sending IPs or throttle email volume to AT&T domains temporarily.
- 24 Hour Wait: Wait 24 hours to see if the issue self corrects as some are temporary
What email marketers say
6 marketer opinions
Reverse DNS (rDNS) failures from AT&T can stem from various issues, including temporary outages, misconfigurations in AT&T's network, or incorrect PTR record setups on the sender's side. Resolution strategies include monitoring AT&T's status, contacting their support, ensuring PTR records are correctly configured and match the sending domain's hostname, considering alternative sending IPs or throttling email volume, and maintaining a high sending reputation. Many suggest monitoring the situation for 24 hours before implementing fixes.
Key opinions
- AT&T Issues: Failures may originate from temporary outages or misconfigurations within AT&T's infrastructure.
- PTR Record Problems: A missing or mismatched PTR record (not matching the HELO/EHLO greeting) is a common cause.
- Impact on Deliverability: rDNS issues at AT&T can negatively affect email deliverability to AT&T users.
- Monitoring Recommended: Experts recommend monitoring the situation and checking AT&T's status pages.
- Patience Advised: Temporary issues may resolve themselves, so monitoring for 24 hours before taking action is suggested.
Key considerations
- Check PTR Records: Verify that your sending IP has a correctly configured PTR record that matches your sending domain.
- Contact AT&T Support: Report the issue to AT&T support for investigation and potential resolution on their end.
- Sending Reputation: Maintain a high sending reputation to mitigate the impact of temporary rDNS issues.
- Alternative IPs/Throttling: Consider using a different sending IP or temporarily throttling email volume to AT&T domains as a workaround.
Marketer view
Email marketer from StackOverflow answers that a common cause is that the IP address being used to send email does not have a PTR record set up, or the PTR record does not match the hostname used in the HELO/EHLO greeting. Ensure your PTR record is correctly configured and matches your sending domain.
25 Aug 2024 - StackOverflow
Marketer view
Email marketer from Email Geeks shares that they are seeing reverse DNS failures from ATT this morning.
9 Nov 2022 - Email Geeks
What the experts say
6 expert opinions
Reverse DNS (rDNS) failures with AT&T are widespread, indicating an issue beyond individual senders. While AT&T is aware, a timeline for resolution is uncertain. Properly configured rDNS records are crucial for email authentication, particularly for mail servers on residential IP addresses to prevent blocking. Maintaining a good sending reputation and ensuring forward and reverse DNS records match are essential for corporate email delivery.
Key opinions
- Widespread Issue: rDNS failures with AT&T are affecting many users, not just isolated cases.
- AT&T Awareness: AT&T is aware of the issue, but a fix ETA is unknown.
- rDNS Importance: Properly configured rDNS is crucial for email authentication and preventing blocking, especially on residential IPs.
- Forward/Reverse DNS Match: Ensuring forward and reverse DNS records match is important for corporate email delivery.
Key considerations
- Monitor AT&T: Keep an eye on AT&T's network status and any announcements regarding a fix.
- rDNS Configuration: Ensure your mail server's rDNS records are correctly configured, particularly if using residential IPs.
- Sending Reputation: Maintain a good sending reputation to mitigate the impact of DNS issues.
- Corporate DNS Setup: Corporate senders must correctly set up their sending infrastructure, including matching forward and reverse DNS records.
Expert view
Expert from Spam Resource, John Levine, responds to a question regarding mail delivery failures and the importance of reverse DNS. He explains the reason email servers will bounce if rDNS cannot be found. He shares that a large fraction of mail servers on residential IP addresses are blocked and they need to have rDNS set up to authenticate who they are.
5 Jan 2023 - Spam Resource
Expert view
Expert from Word to the Wise, Laura Atkins, discusses the importance of maintaining a good sending reputation and proper email authentication. She explains the importance of ensuring valid rDNS records point to the sending servers and that both forward and reverse DNS records match. She discusses the impact of DNS issues on corporate email delivery and the requirement for corporate senders to correctly setup their sending infrastructure.
7 Feb 2024 - Word to the Wise
What the documentation says
5 technical articles
Reverse DNS (rDNS) failures, including those experienced with AT&T, often result from temporary outages, misconfigurations in AT&T's network, or incorrect or missing PTR records. rDNS lookups are essential for identifying mail servers, verifying their identity, gaining trust, and preventing rejection due to anti-spam measures. Resolution strategies include contacting AT&T support, ensuring correct PTR record configuration pointing back to your domain's hostname, and using diagnostic tools to verify the setup.
Key findings
- Multiple Causes: rDNS failures can be caused by AT&T network issues or incorrect PTR record configuration.
- PTR Record Importance: A correctly configured PTR record is critical for resolving an IP address to a domain name.
- rDNS and Trust: Proper rDNS configuration helps mail servers gain trust and avoid being marked as spam.
- Identification: rDNS lookups are a key element in identifying mail servers.
- Beyond AT&T: Problems with rDNS records will cause issues sending email to any mail provider.
Key considerations
- Check AT&T Status: Monitor AT&T's network for any reported outages or issues.
- Contact AT&T: Contact AT&T support to report and request correction of DNS records.
- Verify PTR Records: Ensure your sending IP has a correctly configured PTR record pointing back to your domain's hostname.
- Use Diagnostic Tools: Utilize tools like MXToolbox to diagnose and verify PTR record configuration.
Technical article
Documentation from Digital Ocean explains that a reverse DNS record (rDNS), also known as a PTR record, resolves an IP address to a domain or hostname. Configuring rDNS for your server gives it a hostname that other servers can use to verify its identity. This can help your server gain trust and avoid being marked as spam.
21 Apr 2025 - Digital Ocean
Technical article
Documentation from Google Admin Toolbox explains that rDNS lookups are a key element of identifying mail servers. Problems with rDNS records will cause issues when sending to any mail provider not just AT&T
14 Nov 2023 - Google
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