spf · dkim · dmarc
Email authentication guides
Each page answers one specific question with a copy-ready DNS record. No dashboards, no sign-up.
Google Workspaceinclude:_spf.google.com · 1 lookup
Microsoft 365include:spf.protection.outlook.com · 1 lookup
Zoho Mailinclude:spf.zoho.com · 1 lookup
SendGridinclude:sendgrid.net · 2 lookups
Mailchimpinclude:servers.mcsv.net · 1 lookup
Mailguninclude:_spf.mailgun.org · 3 lookups
Amazon SESinclude:amazonses.com · 1 lookup
Postmarkinclude:spf.mtasv.net · 1 lookup
Klaviyoinclude:klaviyomail.com · 3 lookups
HubSpotinclude:_spf.hubspot.com · 3 lookups
Zendeskinclude:mail.zendesk.com · 1 lookup
Freshdeskinclude:email.freshdesk.com · 7 lookups
Brevoinclude:spf.brevo.com · 1 lookup
ActiveCampaigninclude:emsd1.com · 1 lookup
Salesforceinclude:_spf.salesforce.com · 2 lookups
MailerLiteinclude:_spf.mlsend.com · 1 lookup
Campaign Monitorinclude:_spf.createsend.com · 1 lookup
Constant Contactinclude:spf.constantcontact.com · 1 lookup
Help Scoutinclude:helpscoutemail.com · 1 lookup
Intercominclude:mail.intercomapp.com · 1 lookup
Stripeinclude:spf1.stripe.com · 4 lookups
Mandrillinclude:spf.mandrillapp.com · 1 lookup
Fastmailinclude:spf.messagingengine.com · 1 lookup
Marketoinclude:mktomail.com · 1 lookup
Google Workspace + Mailchimp2 lookups total
Google Workspace + SendGrid3 lookups total
Google Workspace + Zendesk2 lookups total
Google Workspace + HubSpot4 lookups total
Google Workspace + Klaviyo4 lookups total
Microsoft 365 + Mailchimp2 lookups total
Microsoft 365 + SendGrid3 lookups total
Microsoft 365 + Salesforce3 lookups total
Microsoft 365 + HubSpot4 lookups total
Google Workspace + Amazon SES2 lookups total
Google Workspace + Freshdesk8 lookups total
Microsoft 365 + Mailgun4 lookups total
SPF "too many DNS lookups": what it means and how to fix itYour SPF record exceeded the RFC 7208 limit of 10 DNS lookups, so receivers return permerror and behave as if you had no…
SPF permerror: why it happens and what receivers do about itA permerror means a receiver could not evaluate your SPF record at all — usually too many DNS lookups, two SPF records, …
SPF flattening: when it helps, and why it usually backfiresFlattening replaces include: with literal IP ranges to get under the 10-lookup limit. It works, and it also freezes a sn…
Two SPF records on one domain: why it breaks everythingRFC 7208 §3.2 allows exactly one SPF record per domain. With two, receivers return permerror and ignore SPF entirely. Me…
DMARC p=none vs quarantine vs reject: which to use and whenp=none protects nothing, p=reject can block your own mail if you rush it. The safe path is a staged rollout driven by yo…
DMARC record not found: what to publish, and in what orderIf _dmarc.yourdomain.com is empty, nothing tells receivers what to do with forged mail from your domain, and nobody repo…
DKIM selector not found: how to find yoursDNS gives no way to list which DKIM selectors exist on a domain, so "not found" never means "not there". Here is how to …
Why your emails go to spam: the authentication checklist firstBefore rewriting your subject lines, rule out the mechanical causes: SPF over the lookup limit, missing DKIM, no DMARC, …
SPF, DKIM and DMARC explained, in the order they runSPF checks the sending server, DKIM checks the signature, DMARC checks that either one aligns with the domain your recip…
Payment receipts not arriving: email problem or webhook problem?A customer paid and got no confirmation. That is either an email authentication failure or a payment webhook that never …
DMARC alignment: why SPF passes but DMARC still failsDMARC does not care that SPF passed. It cares that the domain SPF passed for matches the domain in the From header your …
SPF void lookups: the second limit nobody mentionsBeyond the famous 10-lookup limit, RFC 7208 also allows at most 2 lookups that return nothing. Dead includes left behind…
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