Summary
The consensus from email marketers, experts, and documentation is that including Google Calendar in SPF records is generally not recommended due to alignment issues, maintenance complexities, and potential for exceeding SPF lookup limits. DKIM is prioritized as it's more robust, survives forwarding, and provides a digital signature ensuring message integrity. SPF validates sending servers but can be less reliable when forwarding occurs. While both SPF and DKIM are important for deliverability and DMARC compliance, focusing on DKIM configuration is crucial. Implementing both SPF and DKIM is often recommended, but simplifying SPF records and regular validation are key to avoid deliverability issues.
Key findings
- Avoid Google Calendar in SPF: It's generally advised not to include Google Calendar in SPF records due to alignment and maintenance concerns.
- DKIM Superiority: DKIM is considered more reliable and robust than SPF, particularly in scenarios involving email forwarding, as it uses digital signatures.
- SPF Complexity Risks: Overly complex SPF records with numerous includes can lead to validation failures and deliverability issues due to exceeding lookup limits.
- Both Methods Matter: While DKIM is favored, both SPF and DKIM are important for comprehensive email authentication and compliance with DMARC.
Key considerations
- Prioritize DKIM Setup: Ensure DKIM is correctly configured for your domain to address Google Calendar sending issues and improve deliverability.
- Simplify SPF Records: Review and simplify SPF records regularly to avoid exceeding lookup limits and potential validation problems.
- Validate SPF Changes: Always validate SPF records after making changes to ensure they remain valid and don't negatively impact deliverability.
- Implement DMARC: Implement DMARC policies to leverage SPF and DKIM effectively and protect your domain from email spoofing.
What email marketers say
9 marketer opinions
Multiple email marketers advise against including Google Calendar in your SPF record due to alignment issues and the potential for SPF records to become overly complex. The consensus is that DKIM is more robust and reliable than SPF, especially in scenarios involving email forwarding, because DKIM provides a digital signature that stays with the email. SPF, which authenticates the sending server's IP address, can break upon forwarding. Implementing both SPF and DKIM is generally recommended, but focusing on DKIM alignment is crucial for improved deliverability and to avoid SPF lookup limits. Correctly configuring DKIM is considered the best solution for Google Calendar sending issues.
Key opinions
- Google Calendar & SPF: Adding Google Calendar to your SPF record is generally not recommended due to potential alignment issues and maintenance complexities.
- DKIM vs SPF Reliability: DKIM is more reliable than SPF, especially in forwarding scenarios, as DKIM signatures persist while SPF can break.
- DKIM Importance: Ensuring DKIM is correctly configured is crucial for resolving Google Calendar sending issues and overall email deliverability.
- SPF Record Complexity: Overly complex SPF records with numerous includes can lead to validation issues and should be avoided.
Key considerations
- Prioritize DKIM: Focus on implementing and maintaining DKIM alignment for improved email deliverability.
- Simplify SPF: Regularly review and simplify your SPF records to avoid exceeding lookup limits.
- Implement Both: While DKIM is more robust, implementing both SPF and DKIM provides a more comprehensive approach to email authentication.
- Monitor SPF Validity: Use online validators to ensure your SPF record remains valid after making changes.
Marketer view
Email marketer from StackOverflow shares that DKIM is generally more robust than SPF because it authenticates the content of the email rather than just the sending server. This makes it less susceptible to issues caused by forwarding or changes in the email's path.
23 Dec 2022 - StackOverflow
Marketer view
Email marketer from GMass answers SPF records are important for email deliverability as they specify which mail servers are authorized to send emails on behalf of your domain, helping prevent spammers from forging your address.
28 Nov 2023 - GMass
What the experts say
4 expert opinions
Experts strongly advise against including Google Calendar in SPF records. DKIM is prioritized as it's crucial for email authentication and survives forwarding, making it more reliable. SPF remains beneficial, particularly if DKIM cannot be implemented. It's important to avoid overly complex SPF records with excessive mechanisms to prevent exceeding lookup limits. Regular validation of SPF records is recommended.
Key opinions
- Avoid Google Calendar in SPF: Including Google Calendar in your SPF record is generally discouraged.
- DKIM Priority: DKIM is the more important authentication method, especially for ensuring deliverability when forwarding is involved.
- SPF as a Backup: SPF is beneficial if DKIM is not feasible, but is secondary in importance.
- SPF Lookup Limits: Overly complex SPF records can exceed lookup limits, invalidating the record.
Key considerations
- Implement DKIM First: Prioritize the implementation and maintenance of DKIM.
- Simplify SPF Records: Keep SPF records simple and avoid excessive includes.
- Validate SPF Records: Regularly validate SPF records using online validators.
- Consider SPF Only if DKIM Fails: If DKIM cannot be implemented, carefully consider SPF as an alternative.
Expert view
Expert from Word to the Wise (Laura Atkins) explains that DKIM and SPF are both important for DMARC compliance but that DKIM is the preferred method because it survives forwarding.
17 Jan 2025 - Word to the Wise
Expert view
Expert from Email Geeks says you absolutely do not want to include Google calendar in your SPF record.
11 Feb 2024 - Email Geeks
What the documentation says
5 technical articles
The documentation indicates that SPF records authorize sending mail servers, and while adding third-party senders might be necessary, Google Calendar isn't specifically mentioned. It emphasizes the importance of staying under the character limit. DKIM provides authentication through digital signatures in email headers, verifying message integrity and origin, while SPF authenticates by verifying sender IP addresses. DKIM is considered more robust due to its ability to survive forwarding. Microsoft recommends using DKIM and DMARC alongside SPF to prevent spoofing. RFC 7208 details SPF technical specifications but doesn't mention Google Calendar. Auth0 clarifies DKIM ensures emails come from authorized sources and haven't been tampered with.
Key findings
- SPF Authorization: SPF records authorize which mail servers can send email on behalf of your domain.
- DKIM Authentication: DKIM uses digital signatures to authenticate the content and source of emails, ensuring integrity.
- SPF Limitations: SPF alone may not be sufficient for preventing spoofing and should be used with DKIM and DMARC.
- DKIM Robustness: DKIM is more robust than SPF because it survives email forwarding.
Key considerations
- Character Limits: Keep SPF records under the character limit to ensure validity.
- Implement DKIM: Implement DKIM for improved email authentication and deliverability.
- Use DMARC: Implement DMARC in conjunction with SPF and DKIM for enhanced email security.
- Monitor Authentication: Regularly monitor email authentication results to identify and address any issues.
Technical article
Documentation from RFC 7208 is the formal specification for SPF, details the technical aspects of how SPF records are interpreted. It explains the mechanisms and qualifiers used in SPF records and provides guidance on how to construct valid SPF policies. It does not mention Google Calendar.
1 Nov 2022 - RFC 7208
Technical article
Documentation from Auth0 clarifies that DKIM adds a digital signature to outbound emails. This allows receiving mail servers to verify that the email was indeed sent from an authorized source and that the message content hasn't been tampered with during transit.
25 Jan 2025 - Auth0
