Establishing a strong email sending reputation is critical for ensuring your messages reach the inbox, and DKIM (DomainKeys Identified Mail) plays a significant role in that. It acts as a digital signature, verifying that an email was sent by the domain owner and hasn't been tampered with in transit. In recent years, the industry has shifted towards stronger encryption, making 2048-bit DKIM keys the recommended standard over the older 1024-bit keys. This move enhances security against spoofing and phishing attempts, which is paramount for maintaining trust with recipients and preventing your emails from landing in the spam folder.
For email service providers like Mailjet, adopting 2048-bit DKIM keys means aligning with current best practices for email authentication. This higher bit length provides a much more robust cryptographic signature, making it significantly harder for malicious actors to forge emails sent from your domain. For businesses, this translates directly to improved deliverability rates and a stronger sender reputation. I often get asked whether this is actually widely supported by ISPs, and the answer is yes, 2048-bit DKIM keys are well-accepted by internet service providers.
This article will guide you through the process of configuring Mailjet to use 2048-bit DKIM keys, ensuring your emails are signed with the highest level of security available through their platform. We'll cover the steps involved, discuss potential challenges you might encounter, and offer practical advice to help you maintain optimal email deliverability.
To fully appreciate the importance of using a 2048-bit DKIM key, it helps to understand what DKIM is and how it functions. DKIM ensures that an email's content hasn't been altered since it left the sender's server and that the sender is authorized to send emails on behalf of the domain. It achieves this through a cryptographic pair: a private key, which signs outgoing emails, and a public key, published in your domain's DNS records, which receiving mail servers use to verify the signature. You can explore the pros and cons of different DKIM key lengths in more detail.
The length of a DKIM key refers to the number of bits used in its cryptographic strength. A 1024-bit key provides a good level of security, but as computing power increases, it becomes more susceptible to brute-force attacks over time. A 2048-bit key, however, offers significantly stronger encryption, making it exponentially more difficult to crack. This increased security is why it's becoming the industry benchmark, especially with major email providers like Mailjet advocating for its adoption.
While both key lengths are currently supported by most email providers, future requirements may mandate longer keys for optimal deliverability and trust. By proactively upgrading to a 2048-bit key, you are not only enhancing your immediate email security but also future-proofing your email infrastructure against evolving threats and stricter authentication standards. Understanding why you should defend your DKIM key size is important for your overall email strategy.
Mailjet's support for 2048-bit DKIM
Mailjet has proactively adopted 2048-bit DKIM keys as their default for new sending domains. This means if you're setting up a new domain with Mailjet, you'll automatically benefit from this enhanced security without any additional steps. For existing domains that might still be using 1024-bit keys, Mailjet provides a straightforward process to upgrade.
To check your current DKIM key length and initiate the upgrade in Mailjet, you'll typically navigate to your account settings, then to the Domains section. From there, select the domain you wish to manage and look for the DKIM settings. Mailjet's interface usually provides an option to generate or regenerate DKIM keys, where you can often select the desired key length. If you don't see an explicit option or encounter any issues, Mailjet's support team is generally helpful in assisting with this process.
The transition process usually involves updating the DNS TXT record for your domain with the new, longer public key provided by Mailjet. Once updated, DNS changes can take some time to propagate globally (up to 48 hours), after which your emails will begin signing with the 2048-bit key. You can also quickly identify your DKIM key length once it's set up.
The process of updating your DKIM key
Upgrading your DKIM key to 2048 bits primarily involves generating the new key pair within Mailjet's platform and then updating your domain's DNS records. Here's a general outline of the process:
Access Mailjet Account: Log in to your Mailjet account.
Navigate to Domains: Go to the Domains section under your account settings.
Manage Domain: Select the specific domain for which you want to update the DKIM key. You might need to click Manage or a similar option.
Generate 2048-bit Key: Look for an option to Generate DKIM Key or Update DKIM. Ensure you select the 2048-bit length option if prompted. You can learn more about tools to generate DKIM keys.
Update DNS Record: Mailjet will provide you with a new DKIM record (typically a TXT record) that contains your 2048-bit public key. You'll need to update this in your domain's DNS management interface. This usually involves replacing your old DKIM TXT record with the new one. Remember to copy the entire record, including the selector, host, and value. Below is an example of what such a record might look like, though the selector and key will be unique to your domain:
Example 2048-bit DKIM TXT recordTXT
selector1._domainkey.yourdomain.com TXT "v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA1/Q... [rest of the key] ...QIDAQAB"
Sometimes, 2048-bit keys can be so long that they exceed the character limit for a single TXT record entry in some DNS providers. In such cases, you might need to split the key into multiple quoted strings within the same TXT record, separated by a single space. For example: "part1ofkey" "part2ofkey". Your DNS provider's documentation or support can usually clarify how to handle TXT records with long values. Mailjet's step-by-step guide on setting up DKIM can be a useful resource here.
Potential challenges and best practices
While the process is generally straightforward, I've seen a few common issues arise. The most frequent one is incorrect DNS entry. A single misplaced character or a forgotten quotation mark can invalidate the entire record, leading to DKIM authentication failures. Always double-check your DNS entries against what Mailjet provides.
Another challenge can be DNS propagation time. Even if you've entered the record correctly, it takes time for these changes to update across the internet. During this period, some emails might still be signed with your old key or fail DKIM authentication altogether. It's crucial to allow sufficient time (up to 48 hours) before expecting consistent results. If you face issues, ensure your DKIM record is published and discoverable. For more on how DKIM selectors work, see our guide on DKIM selector interpretation.
Old approach
Manual management: Dealing with long TXT records in older DNS interfaces often required manual splitting and precise concatenation.
Error prone: Higher chance of syntax errors or character limits being hit, leading to DKIM validation failures.
This could directly impact email deliverability, sending messages to spam or rejecting them outright. The increase in DKIM adoption meant older systems had to catch up, sometimes slowly. Your email deliverability rates could suffer from these issues.
To mitigate these issues, always verify your DKIM record after publishing it. Many online tools can perform a lookup to confirm that your public key is correctly published and valid. Also, consider the recommended DKIM key rotation practices. This proactive approach ensures your emails consistently pass authentication checks, boosting your sender reputation and inbox placement.
Views from the trenches
Best practices
Always use a 2048-bit DKIM key for new domains with Mailjet as it is the default and provides stronger encryption.
Verify your DKIM record immediately after updating your DNS to ensure proper configuration and prevent authentication failures.
Contact Mailjet support if you encounter any difficulties or if your DNS provider has specific requirements for long TXT records.
Common pitfalls
Not accounting for DNS propagation time, which can cause temporary DKIM validation issues after updating records.
Incorrectly splitting the 2048-bit DKIM key in DNS, leading to a malformed record and authentication failures.
Overlooking small typos or extra spaces in your DNS entry, which can invalidate the entire DKIM record.
Expert tips
For very long DKIM keys, some DNS providers might require splitting the key into multiple quoted strings within a single TXT record, separated by a space.
Regularly monitor your DMARC reports to identify any DKIM authentication failures and troubleshoot issues promptly.
Ensure your domain registrar supports 2048-bit keys, as some older systems may have limitations on TXT record length.
Expert view
Expert from Email Geeks says Mailjet support can assist with setting up a 2048-bit DKIM key, as there is no direct user interface option for it.
November 9, 2020 - Email Geeks
Marketer view
Marketer from Email Geeks says managing 2048-bit public keys in DNS can be challenging, especially for less tech-savvy customers trying to make changes.
November 9, 2020 - Email Geeks
Strengthening your email security
Upgrading to a 2048-bit DKIM key with Mailjet is a crucial step towards bolstering your email security and improving deliverability. While Mailjet now defaults to these stronger keys for new domains, it's worth checking and upgrading your existing ones to ensure all your outgoing emails benefit from enhanced cryptographic protection. This move aligns your sending practices with industry best practices and prepares you for future email authentication requirements.
By following the outlined steps and being mindful of DNS propagation and formatting, you can successfully implement 2048-bit DKIM, reducing the risk of your emails being flagged as spam or falling victim to spoofing attacks. This commitment to robust email authentication will significantly contribute to your overall email deliverability success and sender reputation, helping you avoid email blocklists (or blacklists) and ensure your messages consistently reach their intended audience.
