Summary
Generating DKIM public and private keys is a crucial step in setting up email authentication, vital for improving email deliverability and protecting against spoofing. Various tools and methods are available, ranging from convenient online generators to powerful command-line utilities. Each approach offers different levels of control and ease of use, catering to various technical proficiencies and system requirements.
Key findings
- Online generators: Many web-based tools simplify the process, requiring only basic domain information to produce both keys and the corresponding DNS record. These are often preferred for their ease of use and speed.
- Command-line tools: Utilities like OpenSSL and OpenDKIM offer greater control over key parameters (such as length and format) and are commonly used by system administrators and experts.
- Key format importance: The private key must often be in a specific format, such as PKCS#1 RSA private key in PEM format, for successful upload to email service providers (ESPs) or mail servers.
- Underlying technology: Many online DKIM generators internally use OpenSSL, providing a reliable and standardized method for key generation.
Key considerations
- Security of private key: The private key must be kept absolutely secure and confidential. Its compromise can lead to email spoofing issues.
- Compatibility: Ensure the generated keys are compatible with your specific email platform or ESP, paying close attention to required formats and lengths.
- Validation: Always validate your DKIM setup after generating and publishing keys. Tools like DKIM checkers can confirm correct implementation. You can learn more about this in our guide on how to verify DMARC, DKIM, and SPF setup.
- DNS record publishing: The public key needs to be correctly published as a DNS TXT record. This involves adding the key to your domain's DNS settings. For details, refer to how SPF, DKIM, and DMARC records should be placed. A helpful external reference for generating the full record can be found at Sendmarc's DKIM Record Generator.
What email marketers say
Email marketers frequently encounter the need to generate DKIM keys for their email campaigns, often seeking straightforward tools to streamline the process. While they appreciate user-friendly online generators, they can face challenges with specific system requirements or unfamiliar key formats when attempting to integrate these keys into their sending platforms.
Key opinions
- Preference for simplicity: Marketers often prefer tools that generate keys quickly with minimal configuration, especially for testing or initial setup.
- Format issues: A common challenge is ensuring the private key is in the precise format required by the email sending platform, such as PKCS#1 RSA in PEM format, to avoid upload errors.
- System specific requirements: Some systems mandate that users generate their own DKIM keys, but may offer limited support or guidance on the correct procedure or required format.
- Visual clarity: Marketers may prefer keys that appear 'cleaner' or more familiar in structure, as unusual spacing or characters can raise concerns about validity, even if technically correct.
Key considerations
- Tool reliability: It's important to use reputable online DKIM generators to ensure the keys are cryptographically sound and correctly formatted.
- Troubleshooting: Be prepared to troubleshoot if a generated key isn't accepted, often checking error messages for specific format requirements. Our article on troubleshooting DKIM issues can be helpful.
- Post-generation validation: Always validate the DKIM record after publication to ensure it's correctly recognized by mail servers, preventing issues like “no DKIM record found” errors.
- Seeking external resources: When facing difficulties, external guides can provide step-by-step instructions. For example, the IONOS Digital Guide offers advice on creating a DKIM record.
Email marketer from Email Geeks notes that they experienced problems with a DKIM tool, specifically regarding the private key not being in the correct PEM format for upload.
Email marketer from Email Geeks expresses a suspicion that the error encountered when uploading the private key might be a bug in the system rather than an issue with the key itself.
What the experts say
Experts in email deliverability and security typically advocate for a nuanced approach to DKIM key generation. They emphasize the reliability and control offered by command-line tools while acknowledging the practical utility of reputable online generators, especially when these tools utilize industry-standard cryptographic libraries behind the scenes.
Key opinions
- OpenSSL as standard: OpenSSL is widely recognized and used for generating DKIM keys, providing robust cryptographic capabilities and flexibility.
- OpenDKIM utility: OpenDKIM is another frequently cited tool for key generation, often favored by those managing mail servers.
- Online tool transparency: Experts appreciate online generators that are transparent about using well-known libraries like OpenSSL, as this instills confidence in the key's integrity.
- Testing vs. production: Simple online tools like Dkimcore.org are often recommended for testing and educational purposes due to their straightforward nature.
Key considerations
- Private key management: Emphasize secure storage of the private key, as its compromise directly impacts email authentication. For more on DKIM, including key selectors, see our guide on DKIM selector name examples.
- Key length and algorithm: Experts advise using strong key lengths (e.g., 2048 bits for RSA) to ensure cryptographic strength and avoid common errors like DKIM temperrors.
- Validation best practices: Always validate generated keys and the corresponding DNS record. Resources from sites like Spamresource often provide insights into common pitfalls.
- Understanding key types: Differentiating between PKCS#1 and PKCS#8 PEM formats can be crucial for compatibility with certain systems.
Deliverability expert from Email Geeks suggests Dkimcore.org as a simple tool for generating keys, primarily for testing purposes, noting its ease of use.
Deliverability expert from Email Geeks recalls that Dkimcore.org also provides documentation on how to generate DKIM keys using OpenSSL, offering more detailed guidance for advanced users.
What the documentation says
Official documentation and technical guides provide the foundational knowledge for DKIM key generation. These resources often detail the cryptographic principles, recommended algorithms (e.g., RSA), and the precise commands or steps required to generate and manage key pairs. They also emphasize the importance of key selectors and the proper publication of the public key in DNS.
Key findings
- Standard tools: Documentation frequently points to established command-line tools like OpenSSL and ssh-keygen for generating RSA key pairs.
- Key format specifics: There is a strong emphasis on the private key being in the correct PEM format, often specifically PKCS#1, for compatibility with various email systems.
- Public key in DNS: The public key is consistently directed to be published as a DNS TXT record, alongside a specified selector.
- Importance of selectors: Documentation highlights that key selectors are critical for managing multiple DKIM keys for a single domain and for facilitating key rotation.
Key considerations
- Adherence to standards: Always follow the key length and algorithm recommendations (e.g., 2048-bit RSA) outlined in official DKIM RFCs and best practices. These standards also underpin how DMARC works with SPF and DKIM.
- Secure private key handling: Documentation consistently stresses the need to securely store the private key, as it's the cryptographic signature for your emails.
- System-specific guidance: While general tools exist, refer to your email service provider's or mail server's specific documentation for precise instructions on generating and implementing DKIM. This is especially important for services like setting up DKIM for emails from a web server.
- DNS publication details: Pay attention to the exact format required for the DNS TXT record, including quotes and spacing, to ensure proper interpretation by DNS resolvers. Rackspace offers an example in their documentation on creating a DKIM TXT record.
Rackspace Technology Documentation states that users can generate a public-private key pair by utilizing widely available tools such as ssh-keygen on Linux or PuTTYgen on Windows, simplifying the initial setup.
Mailjet Documentation outlines that the first crucial step in setting up DKIM involves configuring it to generate the key pair, which is then followed by placing the public key as a TXT record in the DNS settings.
