Summary
GPT may not recognize updated DMARC records due to a combination of DNS propagation delays, caching mechanisms, and potentially, configuration errors. DNS propagation can take 48-72 hours, with different DNS servers updating at varying intervals. GPT likely caches DMARC records to improve performance, with the TTL of the record determining the caching duration. Some services might have slower update cycles. It's also essential to ensure the DMARC record syntax is correct. Monitoring DMARC reports and using online testing tools can help identify if GPT has trouble validating the record. Clearing your local DNS cache won't affect GPT's resolution.
Key findings
- DNS Propagation Delays: DNS propagation can take 48-72 hours for DMARC updates to be fully recognized across systems.
- Caching: GPT likely caches DMARC records to improve performance, with the TTL influencing caching duration.
- Varying Update Cycles: Different DNS servers and services, including GPT, may have varying update frequencies.
Key considerations
- Record Validation: Ensure the DMARC record syntax is correct using a record checker.
- TTL Configuration: Consider the TTL setting on your DMARC record, as it affects how long GPT caches the record.
- Monitoring and Testing: Monitor DMARC reports and use online testing tools to verify record accessibility and identify validation issues.
- Patience: Allow sufficient time for DNS changes to propagate, accounting for potentially longer delays with specific services.
- Local Cache Clearing: Clearing the local DNS cache does not affect GPT, as you cannot force external resolvers to clear their cache.
What email marketers say
12 marketer opinions
GPT may not recognize updated DMARC records due to several reasons. DNS propagation delays mean that updates can take up to a few days to be fully recognized across all systems, and different DNS servers update at varying frequencies. GPT likely uses cached data for improved performance, which can delay the recognition of updated records until the cache expires; the TTL of the DMARC record influences this caching. Additionally, GPT and other services might have their own update intervals, and GPT could be querying slower DNS servers. It's also important to verify the DMARC record syntax is correct and to monitor DMARC reports to understand how receiving mail servers are interpreting your DMARC policy. Clearing the local DNS cache will not help because you cannot force external resolvers (like Google's GPT) to clear their cache.
Key opinions
- DNS Propagation: DNS propagation delays can take up to a few days for DMARC updates to be recognized across all systems.
- Caching: GPT uses cached data which delays recognizing updates until the cache expires, influenced by the DMARC record's TTL.
- Update Intervals: GPT may have its own update intervals that differ from other DNS servers or manual checks.
- DNS Server Variation: Different DNS servers update at varying frequencies, and GPT might query slower servers.
Key considerations
- Record Syntax: Ensure the DMARC record syntax is correct using a DMARC record checker.
- Monitoring: Monitor DMARC reports to understand how receiving mail servers are interpreting your DMARC policy.
- Verification: Use online DMARC testing tools to verify the record is correctly configured and accessible.
- Lookup Tools: Use external lookup tools such as MXToolbox's DMARC lookup tool to verify independently the DMARC record's validity.
- Local Cache: Clearing the local DNS cache does not affect GPT, as you cannot force external resolvers to clear their cache.
Marketer view
Email marketer from Reddit user shares that it can often take a few days for DMARC updates to be fully recognized by all systems. They suggest checking the TTL (Time to Live) of the DMARC record, as this determines how long resolvers cache the record.
11 Dec 2022 - Reddit
Marketer view
Marketer from Email Geeks asks if the DMARC record has been published for a while.
10 Nov 2021 - Email Geeks
What the experts say
2 expert opinions
GPT might not recognize updated DMARC records primarily due to DNS propagation delays and caching mechanisms. DNS propagation delays occur because different DNS servers update at different intervals. Additionally, GPT likely caches DMARC records to improve performance, causing delays until the cache expires, with the TTL of the DMARC record determining the caching duration.
Key opinions
- DNS Propagation: DNS propagation delays are a common reason, with different DNS servers updating at different intervals, and GPT potentially querying a server that hasn't received the updated record.
- Caching: GPT likely caches DNS records, causing delays until the cache expires, with the TTL of the DMARC record determining the caching duration.
Key considerations
- Record TTL: Consider the TTL (Time To Live) setting on your DMARC record, as it influences how long GPT caches the record.
- Wait Time: Allow sufficient time for DNS propagation to complete across different servers.
Expert view
Expert from Spam Resource (John Levine) explains that DNS propagation delays are a common reason why updated DMARC records might not be immediately recognized. Different DNS servers update at different intervals, and GPT might be querying a server that hasn't yet received the updated record.
10 Mar 2023 - Spam Resource
Expert view
Expert from Word to the Wise (Laura Atkins) answers that GPT likely caches DNS records, including DMARC records, to improve performance. This caching can delay the recognition of updated records until the cache expires. The TTL (Time To Live) of the DMARC record determines how long the record is cached.
29 Mar 2025 - Word to the Wise
What the documentation says
3 technical articles
GPT may not recognize updated DMARC records due to DNS propagation delays and caching. DNS changes can take 48-72 hours to propagate across the internet due to DNS caching by various resolvers. DMARC implementations rely on DNS caching, making changes not immediately visible. While local DNS cache can be cleared, external resolvers like GPT cannot be forced to clear their cache, and GPT updates its cache according to the record's TTL.
Key findings
- Propagation Delay: DNS changes, including DMARC updates, can take 48-72 hours to propagate due to DNS caching.
- DNS Caching: DMARC implementations rely on DNS caching, making changes not immediately visible.
- External Cache Control: External resolvers like GPT cannot be forced to clear their cache; GPT updates its cache according to the record's TTL.
Key considerations
- TTL Setting: Check the TTL of the DMARC record to understand how often resolvers will refresh their cache.
- Patience: Allow sufficient time (48-72 hours) for DNS changes to propagate across the internet.
- Local Cache Clearing: Clearing your local DNS cache will not affect how GPT resolves the DMARC record.
Technical article
Documentation from RFC Editor (RFC 7489 - DMARC specification) outlines that DMARC implementations rely on DNS caching. Resolvers cache DNS records to reduce lookup times, which means changes to DMARC records might not be immediately visible.
24 Feb 2025 - RFC Editor
Technical article
Documentation from Google Workspace Admin Help explains that DNS changes, including DMARC record updates, can take up to 48-72 hours to propagate across the internet. This delay is due to DNS caching by various resolvers.
28 Aug 2023 - Google Workspace Admin Help
Do I need domain host access to update DMARC records?
Do subdomains need their own DMARC records if the main domain has one?
Does Google Postmaster Tools domain reputation include subdomains?
Does Google Postmaster Tools (GPT) data include Google Workspace accounts, or only Gmail.com accounts?
How do I add a TXT record to a DNS configuration for Google Postmaster?
How long does DMARC policy propagation take and how to handle authentication failures?
