Summary
Effective email deliverability and security involve a combination of strategies related to wildcard DNS, DKIM, and DMARC. DKIM best practices include generating a 2048-bit key, regular key rotation, and DNS record publication. DMARC implementation necessitates a policy for handling authentication failures, starting with 'p=none' for monitoring and gradually increasing stringency. Wildcard DNS simplifies subdomain creation but requires careful security planning to avoid unintended matches. Stunt DNS servers further simplify DMARC setup for dynamic subdomains. SPF, DKIM, and DMARC work together for anti-spoofing, with DMARC reporting crucial for understanding deliverability. Key rotation prevents compromises, and RFC 7489 provides the standard. Wildcard TLS certificates present similar risks to wildcard DNS entries.
Key findings
- DKIM Setup: Generate 2048-bit keys, rotate regularly, and publish the DKIM record in DNS.
- DMARC Policy: Implement a DMARC policy, starting with 'p=none' and increasing stringency.
- Wildcard DNS Security: Wildcard DNS simplifies setup but requires careful planning and monitoring to avoid security risks.
- Anti-Spoofing: SPF, DKIM, and DMARC provide anti-spoofing protection.
- Stunt DNS Servers: Stunt DNS servers simplify DMARC setup for dynamic subdomains.
- DMARC Reporting: DMARC reporting is critical for analyzing deliverability.
- Key Rotation: Regular DKIM key rotation mitigates key compromise risks.
- Wildcard TLS Certificates: Wildcard TLS certificates present similar challenges to Wildcard DNS entries.
Key considerations
- DKIM Key Management: Establish a consistent schedule for DKIM key rotation.
- DMARC Enforcement: Gradually increase DMARC policy strictness as confidence grows.
- Wildcard DNS Planning: Plan subdomain coverage carefully when using wildcard DNS.
- DMARC reports analysis: Analyze DMARC reports to identify areas to improve email deliverability.
- TLS certificates: Consider the impact Wildcard TLS certificates may have.
What email marketers say
8 marketer opinions
Several best practices for wildcard DNS, DKIM, and DMARC have been identified. DMARC setup involves publishing a DMARC record in DNS settings, instructing email providers on handling authentication failures, starting with a 'p=none' policy for monitoring. DKIM and DMARC protect against spoofing and phishing; DKIM authenticates, while DMARC builds on SPF and DKIM. Wildcard DNS simplifies subdomain creation but poses security risks, requiring careful planning. DMARC enhances deliverability and brand reputation through continuous monitoring and policy adjustments. Correctly configuring SPF and DKIM is essential, using dedicated sending domains and regular checks. DMARC reporting aids in understanding and addressing deliverability issues. Regular DKIM key rotation mitigates key compromise risks. Finally, Wildcard TLS Certificates also present challenges, use with caution.
Key opinions
- DMARC Setup: Publish a DMARC record in DNS settings and start with a 'p=none' policy for monitoring.
- Security Protection: DKIM and DMARC protect against email spoofing and phishing attacks.
- Wildcard DNS Risks: Wildcard DNS simplifies subdomain creation but can introduce security risks; plan carefully.
- Deliverability Enhancement: DMARC implementation enhances email deliverability and protects brand reputation.
- SPF/DKIM Configuration: Correctly configure SPF and DKIM using a dedicated sending domain and regular checks.
- Reporting Importance: DMARC reporting helps understand and address email deliverability issues.
- Key Rotation: Regular DKIM key rotation mitigates the risk of key compromise.
- TLS Wildcards: Wildcard TLS Certificates presents security challenges, use with caution.
Key considerations
- Monitoring: Continuously monitor DMARC reports and adjust policies for optimal email authentication.
- Planning: Carefully plan subdomain coverage when using wildcard DNS records.
- Security: Address security risks associated with wildcard DNS by implementing appropriate controls.
- Key Management: Implement a process for regular DKIM key rotation to minimize compromise risks.
- TLS Wildcards: Consider all subdomains and security implications when using Wildcard TLS Certificates.
Marketer view
Email marketer from EasyDMARC shares that implementing DMARC enhances email deliverability, protects brand reputation, and prevents phishing attacks. They emphasize the importance of continuous monitoring and adjusting DMARC policies to optimize email authentication.
19 Dec 2024 - EasyDMARC
Marketer view
Email marketer from Proofpoint explains that DKIM and DMARC are essential for protecting your brand from email spoofing and phishing attacks. DKIM authenticates the sender's domain, while DMARC builds upon DKIM and SPF to provide instructions to email receivers on how to handle unauthenticated emails.
3 Dec 2024 - Proofpoint
What the experts say
4 expert opinions
Experts recommend careful planning and monitoring when using wildcard DNS with DKIM/DMARC due to potential unexpected authentication results. A 'stunt DNS server' can simplify DMARC setup, especially for dynamically created subdomains, by only answering queries for existing subdomains. Blog posts cover wildcard DNS with DKIM/DMARC and deployment of stunt DNS servers.
Key opinions
- Wildcard DNS Caveats: Wildcard DNS can simplify setup but lead to unexpected authentication results if not properly managed with DKIM/DMARC.
- Stunt DNS Server: Stunt DNS servers simplify DMARC setup for dynamically created subdomains.
Key considerations
- Planning & Monitoring: Carefully plan and monitor wildcard DNS usage with DKIM/DMARC to avoid authentication issues.
- Stunt DNS Deployment: Consider deploying a stunt DNS server to streamline DMARC configuration for dynamic subdomains.
Expert view
Expert from Word to the Wise explains the relationship between wildcard DNS records and DKIM/DMARC, noting that wildcard DNS can simplify setup but can also lead to unexpected authentication results if not properly managed. Atkins recommends careful planning and monitoring when using wildcard DNS with DKIM/DMARC.
19 Dec 2021 - Word to the Wise
Expert view
Expert from Email Geeks shares a blog post regarding wildcards, DKIM, and DMARC.
1 Nov 2022 - Email Geeks
What the documentation says
5 technical articles
DKIM involves generating a 2048-bit key, regularly rotating keys, and publishing the DKIM record to your DNS. DMARC requires setting up a policy to handle emails failing DKIM/SPF, starting with 'p=none' and gradually increasing stringency. Wildcard DNS simplifies subdomain configuration but needs careful security consideration. SPF, DKIM, and DMARC together provide anti-spoofing protection. RFC 7489 defines the DMARC standard.
Key findings
- DKIM Key Management: Generate 2048-bit DKIM keys, rotate them regularly, and publish the DKIM record.
- DMARC Policy: Implement DMARC by setting up a policy, starting with 'p=none' and increasing stringency gradually.
- Wildcard DNS Security: Use wildcard DNS to simplify configuration, but carefully consider security implications.
- Anti-Spoofing Trio: SPF, DKIM, and DMARC together provide effective anti-spoofing protection.
- DMARC Standard: RFC 7489 defines the DMARC standard and its technical specifications.
Key considerations
- Key Rotation Frequency: Establish a regular schedule for DKIM key rotation to minimize compromise risks.
- Policy Enforcement: Gradually increase DMARC policy stringency as confidence in authentication increases.
- Security Implications: Thoroughly evaluate the security implications of wildcard DNS records before implementation.
- Comprehensive Approach: Implement SPF, DKIM, and DMARC together for optimal email security and deliverability.
- RFC Compliance: Adhere to RFC 7489 specifications when implementing DMARC.
Technical article
Documentation from Microsoft shares that SPF, DKIM, and DMARC work together to provide anti-spoofing protection. Microsoft recommends using all three methods to ensure the best possible email security and deliverability.
5 Jun 2024 - Microsoft
Technical article
Documentation from Google explains that DKIM (DomainKeys Identified Mail) is an email authentication method that helps prevent spammers from forging your domain's email address. Best practices include generating a 2048-bit key, regularly rotating keys, and publishing the DKIM record to your DNS.
1 Nov 2022 - Google
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