Summary
Experiencing reverse DNS failure bounces from AT&T can be a frustrating deliverability issue. These bounces, often indicating that AT&T's mail servers are unable to properly resolve the sender's IP address to a domain name, can lead to significant email delivery disruptions. While sometimes a temporary glitch on AT&T's side, it often points to a need for senders to review their own DNS configurations, specifically their PTR records.
Key findings
- Impact: Some senders reported up to 10% of their AT&T traffic failing due to these reverse DNS issues.
- Error messages: Typical bounce messages include smtp;550 5.7.1 Connections not accepted from servers without a valid sender domain. Fix reverse DNS.
- Scope: The problem can be localized to specific AT&T nodes, such as those related to prodigy.net addresses.
- Resolution: In some cases, AT&T acknowledged internal issues and worked to resolve them, with resolution occurring within days.
Key considerations
- PTR record validation: Ensure your sending IP addresses have correctly configured PTR (pointer) records that resolve to your sending domain. This is a fundamental requirement for many ISPs, including AT&T.
- Reach out to AT&T: If your DNS is correctly configured, contact AT&T's postmaster or support team. Provide them with specific bounce messages, affected IP addresses, and examples of email headers.
- Monitor bounce rates: Continuously monitor your bounce rates, particularly for AT&T, SBCGlobal, and Bellsouth domains, as these providers can sometimes experience specific internal issues. See our guide on why emails to these domains experience high bounce rates.
- Check all authentication records: Verify your SPF, DKIM, and DMARC records are all valid and correctly aligned. A robust authentication setup can sometimes mitigate the impact of minor DNS anomalies. Learn more in our simple guide to DMARC, SPF, and DKIM.
What email marketers say
Email marketers often face a range of deliverability challenges, and reverse DNS failures from major ISPs like AT&T can be particularly vexing. While some might observe these issues as isolated or temporary, others report significant impacts on their email campaigns. The collective experience suggests that while a sender's DNS configuration is crucial, AT&T's systems can sometimes be temperamental, leading to false positives or intermittent problems.
Key opinions
- Shared experience: Many marketers confirm observing sudden, bogus reverse DNS failure bounces from AT&T, sometimes affecting a significant percentage of their traffic (e.g., 10%).
- Specific error messages: Marketers often see specific bounce codes indicating a reverse DNS problem, such as 550 5.7.1 Connections not accepted from servers without a valid sender domain.
- Localized issues: The problem might be localized to specific AT&T mail nodes or regions, making it hard to diagnose universally.
- Direct submission concerns: Some suggest that issues arise when email is submitted directly to the internet from certain IP addresses, potentially bypassing expected mail flows.
- Intermittent nature: Even with correct PTR records, AT&T's servers might intermittently fail to resolve them, indicating an issue on their side rather than the sender's. This aligns with other AT&T related delivery issues, such as why AT&T might be blocking your emails.
Key considerations
- Proactive monitoring: Implement robust monitoring for bounces and deliverability to AT&T domains to quickly identify emerging issues.
- Immediate communication: If widespread issues occur, communicate with your Email Service Provider (ESP) or directly with AT&T's postmaster team.
- Verify DNS consistency: Regularly check that your SMTP banner matches your inbound and rDNS records to prevent mismatch errors. Learn more about DNS related bounces and how to resolve DNS failure hard bounces.
- Document issues: Keep detailed records of bounce messages and the scope of the problem to provide to AT&T if direct contact is needed. This includes instances where AT&T may be imposing a blanket rejection.
Marketer view
Marketer from Email Geeks asks whether others are observing fraudulent reverse DNS failure bounces from AT&T.
Marketer view
Marketer from Spiceworks Community suggests that direct submission of email to the internet from certain IP addresses can lead to reverse DNS issues.
What the experts say
Deliverability experts weigh in on reverse DNS failures from AT&T, often identifying them as a complex interplay between sender configuration and ISP-side processing. While confirming the general importance of correct DNS, experts also acknowledge that large ISPs like AT&T can experience internal issues that lead to legitimate emails being bounced. Their insights often guide marketers on the appropriate steps to take, from direct outreach to ongoing monitoring.
Key opinions
- Initial checks: Experts advise checking your own sending infrastructure first, as false positive DNS failures are typically localized.
- ISP-side issues: Even with correct PTR records, AT&T's servers might fail to resolve them, suggesting an intermittent problem on the ISP's end.
- Direct communication: Experts recommend directly contacting AT&T's postmaster team or official support channels to report widespread issues.
- Ongoing process: Resolving such issues with large ISPs can take time, as their teams investigate and implement fixes, with no immediate estimated time of resolution often provided.
Key considerations
- Verify PTR records: Consistently ensure your IP addresses have valid and properly configured PTR records that match your sending domain. This is a crucial element for establishing trust with receiving servers.
- Proactive outreach: If you observe significant bounce volumes due to reverse DNS from AT&T, compile data and reach out to their support. Persistence is often key.
- Monitor blocklists (blacklists): Keep an eye on blocklists and DNS-based blocklists (DNSBLs) as reverse DNS issues can sometimes lead to listings, impacting overall deliverability. Learn what a DNSBL is and how it affects deliverability.
- Maintain domain reputation: A strong sending reputation built on good sending practices (low spam complaints, good engagement) can help mitigate the impact of temporary ISP-side issues. Our guide on understanding your email domain reputation provides more detail.
Expert view
Expert from Email Geeks notes that their recent test sends to AT&T addresses showed no issues as of a specific time.
Expert view
Expert from SpamResource.com emphasizes the importance of correctly configured PTR records for email authentication and avoiding ISP blocks.
What the documentation says
Official documentation and internet standards provide the foundational requirements for email sending and DNS resolution. These sources highlight that reverse DNS checks are a legitimate part of the SMTP protocol and a common anti-spam measure. While they don't explicitly address specific ISP glitches, they set the expectations for what a compliant email sender's infrastructure should look like, emphasizing the importance of PTR records for trust and deliverability.
Key findings
- RFC compliance: Core RFCs (e.g., RFC 1912, RFC 5321) stipulate that internet hosts should have both forward and reverse DNS records for proper identification and resolution.
- SMTP protocol: The SMTP protocol allows receiving mail servers to check for a client's IP address having a correctly configured PTR record as a valid anti-spam practice.
- DNS hijacking risk: DNS can be susceptible to hijacking, where queries are incorrectly resolved, redirecting traffic and potentially impacting legitimate services. AT&T provides documentation on what DNS hijacking is.
- Authentication reliance: Modern email authentication methods like SPF, DKIM, and DMARC rely heavily on the integrity and correct configuration of underlying DNS records, including PTR. You can learn more about technical solutions for boosting email deliverability.
Key considerations
- Adherence to standards: Ensure your email infrastructure strictly adheres to internet standards (RFCs) for DNS and SMTP, as this forms the basis for trust.
- PTR record accuracy: Verify that your PTR records are correctly set up and maintained for all sending IPs. An inaccurate PTR record is a common reason for reverse DNS failures.
- Monitor DNS health: Regularly check your DNS records for consistency and proper resolution. Tools that test forward and reverse DNS can help identify discrepancies.
- Understanding ISP policies: While RFCs set general guidelines, individual ISPs like AT&T may have stricter or more nuanced policies regarding reverse DNS and sender reputation. Increased email bounces at AT&T often require specific attention.
Technical article
AT&T Business documentation explains that DNS hijacking involves incorrect resolution of DNS queries, redirecting users to unintended sites.
Technical article
Documentation from Network Solutions, Inc. highlights that AT&T's servers sometimes struggle to correctly interpret valid PTR records from senders like Microsoft.
Related resources
6 resources
Related pages
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