Tagged “dmarc” (page 2)
135 articles, page 2 of 3
How to rotate DKIM keys safely
DKIM signing keys decay in security the longer they live. This guide shows how to rotate them using selectors, with full overlap and verification, so legitimate mail never drops a signature or fails DMARC during the change.
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How to add DMARC, SPF and DKIM records on Google Cloud DNS
A precise, Google Cloud DNS-specific walkthrough for publishing TXT and CNAME records for DMARC, SPF and DKIM, including the gotchas that silently break authentication: public versus private managed zones, console versus gcloud TXT quoting, trailing dots on CNAME targets, 255-byte chunking and a TTL strategy for a safe staged rollout to p=reject.
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Email authentication explained for beginners
Email was designed in an era when everyone on the network trusted everyone else, so it shipped with no built-in way to prove who actually sent a message.
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How to add DMARC, SPF and DKIM records on IONOS
A precise, IONOS-specific walkthrough of adding TXT and CNAME records for DMARC, SPF and DKIM in the IONOS DNS editor, covering the root-versus-host gotcha, TXT chunking, CNAME flattening, TTL and a safe sequence to p=reject.
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Why your domain can be spoofed, and how to stop it
If you own a domain and have never published a DMARC record, anyone on the internet can send email that appears to come from you.
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DMARC alignment explained, with examples
A message can pass SPF and verify DKIM yet still fail DMARC. The reason is alignment. This guide explains SPF and DKIM alignment, relaxed versus strict mode, and the exact DMARC pass rule, with five worked examples of messages that pass and fail.
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How to add DMARC, SPF and DKIM records on Namecheap
A precise, Namecheap-specific walkthrough for adding DMARC, SPF and DKIM records in the Advanced DNS editor, covering the host-field gotchas, TXT chunking, CNAME targets, TTL and the safe path from p=none to p=reject.
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The five DNS records that protect your email
Email was designed in an era of trust. The original protocol, SMTP, lets any server on the internet claim to send mail as anyone.
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Ten common DMARC mistakes and how to avoid them
The configuration and rollout mistakes that most often break mail or leave domains exposed, from jumping straight to p=reject to ignoring report drift, and exactly how to avoid each one.
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How to add DMARC, SPF and DKIM records on OVH
A precise, OVH-specific walkthrough for adding SPF, DKIM and DMARC records in the OVH DNS zone editor, covering the apex naming rule, TXT chunking for long DKIM keys, CNAME trailing dots and TTL behaviour.
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Reading your first DMARC aggregate report
A field-by-field walkthrough of a DMARC aggregate (RUA) XML report: metadata, source IPs, disposition, SPF and DKIM results, alignment, and spotting spoofers.
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Protecting parked and no-mail domains
Domains that never send mail are the easiest to secure and the most commonly left wide open. Here is how to lock down parked, legacy and campaign domains with SPF -all, DMARC p=reject and a null MX so they cannot be spoofed, with zero deliverability risk.
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How to add DMARC, SPF and DKIM records on AWS Route 53
A precise, Route 53-specific walkthrough for publishing SPF, DKIM and DMARC: empty Record name versus host names, TXT quoting and 255-character chunking, why DKIM CNAMEs must never become Alias records, and TTL strategy for a safe staged path to p=reject.
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Mailing lists, DMARC and ARC
Mailing lists are one of the few places where correct, well-behaved email authentication still breaks for reasons that are nobody's fault.
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DMARC for Google Workspace
A new Google Workspace domain ships with no DKIM signing, an SPF record you must add yourself, and no DMARC policy at all. This guide walks the exact order to fix that: get SPF right under the 10-lookup limit, switch on DKIM in the Admin console, then ratchet DMARC from monitoring to full reject without breaking a single legitimate message.
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How to add DMARC, SPF and DKIM records on Squarespace
A precise, Squarespace-specific walkthrough of adding TXT and CNAME records for DMARC, SPF and DKIM in the Squarespace DNS editor, including the gotchas that actually break setups: the doubled-domain Host field, TXT chunking, CNAME-at-apex, SPF flattening and TTL.
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Aliases, .forward files and DMARC
An alias looks like the most innocent thing in email. You point sales@yourcompany.com at three colleagues, you set up info@ to land in a shared mailbox, a member of staff configures their university address to drop.
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DMARC for Microsoft 365
A practical, ordered guide to email authentication on Microsoft 365: build a complete SPF record for Exchange Online, enable DKIM signing with Microsoft's two selector CNAMEs, and walk DMARC safely from p=none through quarantine to p=reject without breaking your mail.
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How to add DMARC, SPF and DKIM records on Wix
A precise, Wix-specific walkthrough of adding TXT and CNAME records for DMARC, SPF and DKIM in the Wix DNS editor, covering the real gotchas: relative host names, long-TXT chunking, CNAME targets without a trailing dot, the one-SPF-record rule and TTL during testing.
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Amazon SES at scale: deliverability and DMARC
Amazon SES is deceptively easy to start with and deceptively hard to run well at volume. Verifying a domain, adding three DNS records and firing your first message takes an afternoon.
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The DMARC pct tag and sampling, explained
The pct tag was DMARC's sampling dial until RFC 9989 removed it. How legacy receivers still apply it, why pct=0 was a downgrade trap, and how to migrate off it safely.
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p=none vs quarantine vs reject
The three DMARC policies compared: what p=none, p=quarantine and p=reject each tell receivers to do with failing mail, and how to progress between them safely without breaking your own email.
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The DMARC record explained, tag by tag
A plain-English reference to every tag in a DMARC record: v, p, sp, rua, ruf, pct, adkim, aspf, fo, rf and ri. What each one does, the exact syntax it expects and the sensible default to reach for.
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How invoice fraud begins with a spoofed domain
Invoice fraud usually starts with a forged sender address. Here is how exact-domain spoofing works, what DMARC at p=reject stops, and what it does not.
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What DMARC reports do and do not tell you
Passing DMARC is permission to be judged on your merits, not a guaranteed seat in the inbox. Here is how to read aggregate reports for exactly what they measure, identity and authentication, without mistaking a perfect pass rate for good deliverability or panicking at failures that do not matter.
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DMARC aggregate vs forensic reports
DMARC sends two kinds of feedback: aggregate (rua) reports and forensic (ruf) reports. They answer different questions and carry very different privacy risks. This guide explains exactly what each contains, why forensic reports have all but vanished, the data-protection considerations on both sides, and how to turn the aggregate data into a safe path from p=none to p=reject.
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How to reach DMARC p=reject without breaking email
The staged playbook to DMARC enforcement with no email outage: inventory senders, fix SPF and DKIM, ramp p=none to p=reject, and lock down subdomains.
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Subdomain policy: the DMARC sp tag
An enforced root domain at p=reject protects exactly one address and can leave every subdomain spoofable. Here is what the DMARC sp tag does, the inheritance trap that catches teams mid-migration, and how to close the gap safely without bouncing legitimate subdomain mail.
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How email spoofing actually works
Email spoofing takes no password and no exploit: SMTP simply trusts whatever the sender types into the From field. This guide traces the mechanism from the raw SMTP conversation, through the crucial split between the envelope-from used for delivery and the header-from a human reads, to the three layered controls (SPF, DKIM and DMARC alignment) that finally make forging your domain fail.
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Email transport security: STARTTLS, MTA-STS, DANE
DMARC proves who sent a message, but it does nothing to protect that message while it crosses the internet. Here is how opportunistic STARTTLS, MTA-STS, DANE and TLS-RPT work together to keep inbound mail encrypted in transit, why STARTTLS alone is trivially downgraded, and the safe order to deploy enforcement without bouncing legitimate mail.
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DMARC external destination verification
Sending DMARC reports to an address outside your own domain is an external destination, and RFC 7489 requires the receiving domain to authorise it first. Here is exactly which DNS record to publish, where, and why reports silently vanish without it.
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Why DMARC fails when SPF and DKIM pass
SPF passes, DKIM passes, yet DMARC still fails on legitimate mail. The cause is almost always alignment: both checks authenticated a domain other than the one in your From header. Here is how to find the misaligned identifier in a single message header and across all sources in your aggregate reports, then fix each cause.
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How to enable DKIM in Microsoft 365
Microsoft 365 signs your mail with a shared Microsoft domain by default, which does nothing for DMARC alignment. This guide walks through enabling DKIM signing for your own custom domain end to end: finding the exact CNAME values, publishing the two selector records, switching signing on, and verifying the result really passes.
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DMARC says quarantine but mail still reaches the inbox
A quarantine policy does not always mean the spam folder. Here is why failing mail still lands in the inbox: pct sampling, alignment, receiver discretion, DNS caching, and exactly what to check.
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How to fix SPF PermError
SPF PermError means a receiver tried to evaluate your SPF record and gave up, so SPF stops counting towards DMARC. This guide diagnoses PermError, TempError and the ten-lookup limit, then walks through a step by step repair process.
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DMARC reporting: mailto vs https URIs
The rua and ruf tags accept both mailto: and https: URIs, but almost every working DMARC record uses mailto: only. Here is why HTTPS delivery is dead in practice, how the size-limit suffix and external destination verification work, and how analysers ingest the gzipped XML.
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Why forwarding breaks email authentication
Forwarding almost always breaks SPF and sometimes breaks DKIM too. Here is what survives a forwarding hop, why DKIM is the mechanism that carries your authentication through, how DMARC's one-aligned-pass rule copes, and where ARC rescues mailing-list mail.
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DMARC reports show sources I do not recognise
Unknown sending IPs in your DMARC aggregate reports are normal, not an emergency. Here is a reliable four-question triage to tell shadow IT and forwarders from real spoofers, and exactly what to do with each.
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Lookalike and cousin domains
Attackers register confusable domains that authenticate perfectly and slip past your defences, because your DMARC policy protects only the exact name it is published under. Here is how homoglyph and cousin domains work, the precise reason a p=reject policy cannot touch them, and the layered plan that actually defends your brand.
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DMARC vs SPF vs DKIM: how they fit together
SPF, DKIM and DMARC are named together so often that they blur into one thing. They are not. This is a clear comparison of what each record actually proves, why SPF and DKIM are blind to the From line your recipients trust, and how DMARC ties them together with alignment and policy.
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One-click unsubscribe: the List-Unsubscribe requirement
Google, Yahoo and Microsoft now require working one-click unsubscribe on bulk mail. Here is what the List-Unsubscribe and List-Unsubscribe-Post headers are, how RFC 8058 one-click actually works on the wire, how to implement it correctly, and why it sits alongside SPF, DKIM and DMARC on the same deliverability checklist.
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PCI DSS 4.0, cyber-insurance and email authentication
PCI DSS 4.0 Requirement 5.4.1 and cyber-insurance questionnaires now treat anti-phishing as a measurable control. Here is exactly how that intersects with DMARC, SPF and DKIM, what counts as evidence, and how to reach enforcement without breaking your own mail.
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Phishing and business email compromise
Business email compromise rarely uses malware: it borrows trust by impersonating people you already deal with. Here is how phishing and BEC work, where the money goes, and the layered defences, with DMARC at enforcement as the load-bearing wall.
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Email authentication for ActiveCampaign: SPF, DKIM and DMARC
An ActiveCampaign-specific guide to email authentication: the exact SPF include, CNAME-based DKIM, the custom return-path that aligns SPF, and a staged path to DMARC p=reject without breaking your campaigns or automations.
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Publishing DMARC, SPF and DKIM on common DNS hosts
Exact steps to publish SPF, DMARC and DKIM on Cloudflare, GoDaddy, Namecheap and AWS Route 53, plus the two gotchas that break most setups: TXT chunking on long DKIM keys and CNAME coexistence at the apex.
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Email authentication for Amazon SES: SPF, DKIM and DMARC
Amazon SES passes SPF and DKIM by default but on amazonses.com, so nothing aligns under DMARC. Here is the exact SES include, Easy DKIM and its CNAME selectors, the custom MAIL FROM that fixes SPF alignment, and the staged path to p=reject.
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Why Gmail, Yahoo and Microsoft now require DMARC
Gmail, Yahoo and Microsoft now require SPF, DKIM and DMARC from bulk senders. Here is what each demands, what "require" really means, and how to comply.
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How sender reputation works
Mailbox providers decide where your mail lands based on sender reputation, a private estimate built from how recipients react to your messages and how cleanly you send. This guide explains domain and IP reputation, the signals that raise and lower them, how to warm up a new sender, and why aligned SPF, DKIM and DMARC are what keep the reputation you build genuinely yours.
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