How to Clear the DNS Cache of Our DMARC Checker

If you’ve recently updated your DKIM, SPF, or DMARC records and our checker still shows old results, it’s likely due to DNS caching.

Our DMARC checker uses Google Public DNS for lookups. TXT records, like those used for DKIM, SPF, and DMARC, typically have a TTL (Time to Live) of 1800 (30 min) or 3600 (1 hour), though longer values are possible. Until this TTL expires, Google Public DNS might serve cached records instead of fresh ones.

To force Google Public DNS to fetch updated records, use their Flush Cache tool:

• DKIM: Enter the full selector domain, e.g., selector._domainkey.example.com, and select TXT as RR Type.
• SPF: Enter the main domain, e.g., example.com, and select TXT.
• DMARC: Enter _dmarc.example.com and select TXT.

Click Flush Cache, wait a few seconds, and Google’s DNS server should now retrieve fresh records.

Note: Some domains use CNAME records instead of TXT records, meaning the DNS record doesn't contain the value itself but points to another domain. This is common for DKIM keys managed by email providers.