Summary
Google bounces related to PTR records, even when setups appear compliant, can stem from various interconnected DNS misconfigurations and policy enforcements. These include the hostname the IP points to resolving to incorrect IPs, the PTR record itself not matching the sending IP, a mismatch between the hostname used in the HELO/EHLO greeting and the IP address, generic PTR records on shared IPs, IP reputation problems, discrepancies between the HELO domain and PTR record domain, DNS propagation delays, the absence of Forward Confirmed Reverse DNS (FCrDNS), and stricter security measures by ISPs. Methodical diagnosis, accurate DNS record matching, proper hostname resolution, and consistent monitoring are vital for resolving these issues.
Key findings
- Hostname Resolution Errors: Incorrect IP addresses being resolved by hostnames can trigger bounces.
- PTR/IP Mismatch: The PTR record must accurately reflect the sending IP.
- HELO/EHLO Discrepancies: The hostname used in the HELO/EHLO greeting should match the sending IP's resolution.
- Shared IP Limitations: Generic PTR records on shared IPs can cause issues.
- IP Reputation Impact: Poor IP reputation affects deliverability, even with correct PTR records.
- Domain Inconsistencies: Discrepancies between HELO domain and PTR record domain create problems.
- Propagation Delays: DNS changes require time to propagate fully.
- FCrDNS Requirement: Forward Confirmed Reverse DNS (FCrDNS) is essential.
- Policy Enforcement: ISPs enforce stricter security measures related to PTR records.
- DNS Misconfigurations: General DNS problems often cause deliverability failures.
Key considerations
- Correct Hostname Mapping: Ensure the hostname associated with the IP resolves to the correct IP addresses.
- Verify PTR Configuration: Double-check the PTR record with your ISP/hosting provider.
- Align HELO/EHLO: Make sure the hostname used in HELO/EHLO is correctly configured.
- Dedicated IP: Consider using a dedicated IP address.
- Monitor IP Reputation: Regularly monitor and maintain your IP's reputation.
- Confirm DNS Alignment: Ensure alignment between domains and DNS records.
- Allow Propagation Time: Wait for DNS changes to fully propagate.
- Implement FCrDNS: Set up Forward Confirmed Reverse DNS (FCrDNS).
- Diagnose DNS Methodically: Methodically diagnose DNS issues, looking at all possible areas of failure.
- Perform Regular Checks: Use tools to regularly check and monitor DNS health.
What email marketers say
10 marketer opinions
Even when PTR records appear compliant, Google bounces can occur due to several reasons. Common issues include the PTR record not matching the sending IP, mismatches between the hostname used in the HELO/EHLO greeting and the IP address, generic PTR records on shared IPs, IP reputation problems, discrepancies between the HELO domain and PTR record domain, DNS propagation delays after changes, and the absence of Forward Confirmed Reverse DNS (FCrDNS). Additionally, stringent security measures by ISPs and inconsistencies in forward and reverse DNS records can trigger bounces.
Key opinions
- PTR Mismatch: The PTR record must accurately match the sending IP address. Use tools to verify.
- HELO/EHLO Mismatch: The hostname used in the HELO/EHLO greeting should resolve to the sending IP.
- Shared IP Issues: Generic PTR records on shared IPs may cause bounces; consider a dedicated IP.
- IP Reputation: A poor IP reputation can lead to bounces despite correct PTR records.
- Domain Alignment: The domain in the HELO command must align with the domain in your PTR record.
- DNS Propagation: Allow sufficient time for DNS changes to propagate fully.
- FCrDNS Importance: Forward Confirmed Reverse DNS (FCrDNS) is crucial; ensure the PTR record resolves to an A record matching the IP.
- DNS Inconsistencies: Check for inconsistencies between forward and reverse DNS records.
Key considerations
- Verify PTR Record: Double-check with your ISP or hosting provider to ensure your PTR record is correctly configured.
- Monitor IP Reputation: Regularly check and maintain your IP's reputation to avoid being flagged as spam.
- DNS Health Checks: Utilize DNS health check tools to identify and resolve inconsistencies in your DNS setup.
- Consider Dedicated IP: If using a shared IP, evaluate the benefits of switching to a dedicated IP address for better control over your sending reputation.
- Review DNS Configuration: Carefully review your DNS configuration, paying special attention to the HELO domain, PTR records, and A records, to ensure alignment and accuracy.
Marketer view
Email marketer from Email Geeks shares Google documentation stating that the sending IP address must match the IP address of the hostname specified in the PTR record.
22 Dec 2021 - Email Geeks
Marketer view
Email marketer from StackOverflow indicates that even with a PTR record, a mismatch between the hostname used in the HELO/EHLO greeting and the IP address can cause bounces. He suggests ensuring the hostname presented during the SMTP handshake resolves to the sending IP.
19 Jul 2021 - StackOverflow
What the experts say
3 expert opinions
Google bounces related to PTR records, despite seemingly compliant setups, can stem from various underlying DNS misconfigurations. These include hostname resolution issues where the IP points to incorrect addresses, the absence of Forward Confirmed Reverse DNS (FCrDNS), and general DNS issues requiring methodical diagnosis. Ensuring correct IP-to-hostname mapping and valid FCrDNS is critical for resolving these bounces.
Key opinions
- Hostname Resolution: Incorrect hostname resolution, where the IP points to the wrong addresses, is a key issue.
- FCrDNS Importance: Lack of Forward Confirmed Reverse DNS (FCrDNS) is a common problem; PTR record must resolve to a matching A record.
- DNS Diagnosis: Methodical diagnosis of DNS issues is crucial for identifying the root cause of deliverability problems.
Key considerations
- Check Hostname Mapping: Verify that the hostname the IP points to resolves to the correct IP addresses and remove any obsolete DNS records.
- Implement FCrDNS: Ensure your PTR record is configured such that it resolves to an A record that matches the sending IP address.
- Systematic DNS Review: Perform a comprehensive review of your DNS settings, starting with common issues, to pinpoint any underlying misconfigurations.
Expert view
Expert from Email Geeks explains that the issue is not the PTR record itself, but the hostname the IP points to resolving to incorrect IPs. Google might be enforcing new requirements from last October. The user needs to change the DNS record for o1178.service.musclefood.com to point to 149.72.183.96 and delete the existing record that points to 18.130.118.158, ensuring no other services are using the old hostname.
5 Apr 2023 - Email Geeks
Expert view
Expert from SpamResource suggests that problems with email delivery require methodical diagnosis, including checking common DNS issues. Although they don't directly answer the PTR problem, they emphasise you should start with common problems, and these are normally in the DNS settings.
27 Jan 2022 - SpamResource
What the documentation says
4 technical articles
Google bounces related to PTR record issues, despite apparent compliance, often arise due to misconfigurations in reverse DNS. Key requirements include ensuring the sending IP address matches the hostname specified in the PTR record and that forward and reverse DNS records are accurately associated and matched. Incorrectly configured records are a common cause of deliverability problems, necessitating verification and proper association with the domain.
Key findings
- PTR Record Matching: The sending IP address must match the hostname specified in the PTR record.
- Forward/Reverse DNS Match: Forward and reverse DNS records must be accurately associated and matched.
- Incorrect Configuration: Incorrectly configured DNS records are a prevalent cause of email deliverability issues.
- rDNS Resolution: rDNS lookup, using the PTR record, resolves an IP address to a domain name and requires precise association.
Key considerations
- Verify IP/Hostname Match: Ensure the sending IP address corresponds precisely to the hostname specified in your PTR record.
- Associate DNS Records: Verify that forward and reverse DNS records are correctly associated with your domain and IP.
- Utilize Verification Tools: Use tools like MXToolbox to verify that your reverse DNS lookup matches your sending domain and IP.
- Regular DNS Review: Periodically review and confirm your DNS configurations to identify and correct any misconfigurations that may arise.
Technical article
Documentation from Google Workspace Admin Help explains that the sending IP address must match the IP address of the hostname specified in the Pointer (PTR) record. This is a requirement for sending emails to Gmail and helps prevent your mail from being marked as spam.
12 Jan 2023 - Google Workspace Admin Help
Technical article
Documentation from Microsoft Docs clarifies that a reverse DNS (rDNS) lookup, using the PTR record, resolves an IP address to a domain name. It emphasizes that the forward and reverse DNS records should match. If they don't, some mail servers, including Google, may reject the email.
6 Aug 2023 - Microsoft Docs
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