What Is DMARC Compliance and How to Achieve It

September 18, 2025 • By DMARCFlow Team

Email spoofing and phishing remain common problems. Attackers can forge the sender address and trick recipients into trusting malicious messages. Domain based Message Authentication Reporting and Conformance, known as DMARC, builds on Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM). DMARC lets domain owners publish a policy in DNS that tells mail receivers how to handle unauthenticated email and generates reports that show how their domains are used. DMARC compliance means setting up and aligning SPF and DKIM so that legitimate messages pass while fraudulent ones are blocked or quarantined.

Understanding DMARC and compliance

DMARC authenticates the domain used in the "From" header. A message passes DMARC when the domain in the From field matches a domain that has been validated by SPF or DKIM. Alignment can be relaxed, where only the organisational parts of the domains match, or strict, where the fully qualified domains are identical. DMARC compliance therefore means configuring SPF and DKIM, publishing a DMARC record and ensuring that outgoing messages align with one of these authentication methods. Once your policy is enforced, unauthenticated messages are quarantined or rejected to protect recipients and your brand.

Why DMARC compliance matters

Phishing and business email compromise are among the most frequent cyber attacks. DMARC helps stop fraudulent messages before they reach users and protects other organisations from receiving emails that misuse your domain. Implementing DMARC improves the trustworthiness of your email and protects customers and partners.

Major mailbox providers recognise this. Gmail and Yahoo require bulk senders that deliver more than five thousand messages per day to implement SPF, DKIM and DMARC, maintain valid forward and reverse DNS records, keep spam rates low and support one click unsubscribe. These requirements mean that DMARC compliance is no longer optional for organisations that send large volumes of email. Industry mandates also move in this direction; the Payment Card Industry Data Security Standard (PCI DSS) will require SPF, DKIM and DMARC for compliance assessments from the end of March 2025. Adopting these controls early reduces the risk of penalties and improves deliverability.

Key components of DMARC compliance

SPF: authorised senders

SPF identifies which servers are allowed to send email on behalf of your domain. A valid SPF record lists all authorised IP addresses and services and must be kept up to date. It is important to keep the record short so that it does not exceed the limit of ten DNS lookups. A centralised management system makes it easier to maintain SPF across multiple domains and prevents misconfigurations.

DKIM: digital signatures

DKIM adds a cryptographic signature to each message. Your mail system signs selected header fields and the message body using a private key. The corresponding public key is published in DNS so that receiving servers can verify the signature and detect tampering. Current guidance recommends keys of at least 1024 bits and encourages 2048 bit keys for stronger security. Managing keys for multiple domains can be complex; a platform that automates key generation and rotation reduces the risk of weak or expired signatures.

DMARC record

A DMARC record is a TXT entry at _dmarc.yourdomain.com. It must include the version (v=DMARC1), a policy (p=) and one or more reporting addresses (rua=). Optional tags let you set alignment for SPF (aspf) and DKIM (adkim), control the percentage of messages that are subject to the policy (pct) and specify forensic reporting (ruf). To begin, publish a monitoring policy: v=DMARC1; p=none; rua=mailto:reports@yourdomain.com; aspf=r; adkim=r; pct=100. This lets you collect reports without affecting message delivery. Review the reports, identify legitimate senders and fix authentication issues. When you are confident that all authorised email passes SPF or DKIM, change the policy to p=quarantine so failing messages go to spam and later to p=reject to block them entirely.

Alignment modes

Alignment ensures that the From domain matches the domain authenticated by SPF or DKIM. In relaxed mode the organisational domains match; for example, a signature from example.com aligns with a From address of alerts@news.example.com. In strict mode the fully qualified domains must match exactly. You can set relaxed or strict alignment for SPF and DKIM through the aspf and adkim tags in your DMARC record. Use relaxed alignment during initial deployment and tighten alignment when you have full control over all senders.

Reporting

Aggregate reports, known as RUA reports, summarise how many messages passed or failed SPF, DKIM and alignment. Forensic reports, known as RUF, provide details about individual messages. These reports may include IP addresses and other information that is considered personal data under privacy laws. In Europe, a data minimising approach helps meet the requirements of the General Data Protection Regulation. If you do not need detailed RUF reports you can omit the ruf tag or work with a provider that redacts sensitive data.

Steps to achieve DMARC compliance

  1. Inventory your domains and senders. Identify every domain you own and all services that send email on your behalf, including marketing platforms, support systems and transactional services. Unknown senders are the main reason messages fail DMARC.
  2. Implement SPF for each sending domain. Publish an SPF record listing authorised IP addresses and services. Remove deprecated systems and use include mechanisms cautiously to stay within the DNS lookup limit.
  3. Enable DKIM signing. Generate 2048 bit DKIM keys for each domain. Configure your mail systems to sign outgoing mail and publish the public keys in DNS. For third party senders, ask the provider to sign using your domain's DKIM keys.
  4. Create a DMARC record. Start with a monitoring policy, collect reports and adjust SPF and DKIM until all legitimate mail passes.
  5. Monitor and analyse reports. Use a tool or service to parse aggregate reports, identify unknown senders and fix misconfigurations. Regular reporting helps you react quickly to authentication failures and spoofing attempts.
  6. Progress to enforcement. Once you have verified that all legitimate email is authenticated and aligned, change the policy to quarantine. After further monitoring, move to reject. Continue to review your SPF and DKIM records whenever services change.
  7. Meet mailbox provider requirements. If you send more than five thousand messages per day to providers such as Gmail or Yahoo, ensure that SPF, DKIM and DMARC are in place, maintain valid forward and reverse DNS entries, keep your spam rate below 0.3 percent and support one click unsubscribe. Use Transport Layer Security when sending mail and avoid impersonating provider domains.
  8. Prepare for industry mandates. For organisations subject to PCI DSS or other regulations, implement SPF, DKIM and DMARC now so you meet future compliance requirements without disruption.

Why DMARCFlow is a strategic choice

Achieving DMARC compliance can be resource intensive. Parsing XML reports by hand and updating DNS entries across many domains is error prone. DMARCFlow was designed to simplify this process and offers several advantages that make it a strategic choice:

  • Centralised SPF management. DMARCFlow centralises SPF configuration, helps you build concise records and prevents exceeding the DNS lookup limit. This makes it easier to manage multiple sending services and keep records up to date.
  • Multi domain DKIM management. The platform generates and manages DKIM keys for multiple domains and ensures that every email is signed correctly. Automated key rotation reduces the risk of weak or expired keys.
  • Automated reports and insights. DMARCFlow collects DMARC reports, converts them into daily and weekly summaries and highlights issues that need attention. Built in analytics and machine learning detect patterns that might indicate phishing campaigns or misconfigured senders.
  • Fast set up and easy use. A guided wizard takes less than ten minutes to get you started. It walks you through the configuration of SPF, DKIM and DMARC and tests each step. The interface supports multiple domains, role based permissions and clear dashboards.
  • GDPR compliant data processing. DMARCFlow does not store unnecessary personal data and processes reports in accordance with the General Data Protection Regulation. All data is stored exclusively in the European Union, which is important for organisations with strict privacy requirements.
  • Early risk detection. By providing clear reports and predictive analytics, DMARCFlow helps you detect phishing attempts and configuration problems early. This allows you to take action before issues affect your users or reputation.

These features make DMARCFlow a practical platform for organisations that want to achieve and maintain DMARC compliance. Other tools offer similar functionality, but DMARCFlow combines ease of use, technical depth and European data protection into a robust email security strategy.

Conclusion

DMARC compliance is more than a best practice; it is becoming a requirement for large senders, financial companies and anyone who values their brand and the trust of their customers. Compliance involves implementing SPF and DKIM, publishing a DMARC record, ensuring alignment, monitoring reports and progressing toward enforcement. Adhering to new requirements from mailbox providers and meeting industry mandates ensures that your messages continue to reach their destination and that your organisation remains trustworthy.

Using a specialised platform such as DMARCFlow can greatly simplify this process. With centralised management, automated reporting, GDPR compliant processing and rapid deployment, DMARCFlow provides a strategic path to achieving and maintaining DMARC compliance.