To thrive in today’s digital world laden with cybersecurity threats, you must implement certain measures to tighten your security. One way is to guard your email ecosystem with authentication protocols that ensure authorized emails are sent from your domain. Now, when you set up email authentication protocols like SPF, DKIM, and DMARC, you should be very careful because even a tiny error can lead to big problems. One such issue is the invalid DKIM signature, which can wreak havoc on your entire email security strategy.
If you do not want your emails to be tampered with and ruin your brand reputation, you should fix this error! Not sure how to go about it? This article is your ultimate guide to resolving this issue so that your emails will be delivered to recipients securely and efficiently.
Understanding DKIM signatures
DKIM, or DomainKeys Identified Mail, is an email authentication protocol that assures an email has not been tampered with on the way to its recipient’s inbox. It uses two keys to do this— a public and a private key. Your server uses a private key to create a unique digital signature that will be added to the email header. As for the public key, it is published in the DNS record for the recipient’s server to verify the authenticity of the sent message.
Unlike a typical email signature that you find at the bottom of the email, a DKIM signature is added to the email header itself and isn’t visible to users. Yet it assures your recipients that the emails they are receiving haven’t been manipulated or altered in anyway by a cyberattacker trying to gain unauthorized access to their system. So, if this DKIM signature isn’t properly configured or is invalid, it can lead to a lot of security risks and email deliverability issues.
For instance, if the DKIM signature does not match the public key in your DNS record, then it becomes impossible for the recipient’s server to verify the authenticity of the email. Moreover, in such cases, when the spam filters cannot verify your emails as authentic, they might as well flag your emails as suspicious or even reject them outrightly.
Signs of an invalid DKIM signature
We have learned that an invalid email can significantly impact your email deliverability and security, but without a complete understanding of how to fix this problem, this information isn’t good enough. To resolve this issue, you first need to know what’s wrong with your DKIM signature. Only then can you take the necessary steps to correct it. Here are some signs that indicate your DKIM signature may be invalid:
- If the domain in your DKIM signature does not match the domain from which the email came, the receiving server will view it as suspicious and might even mark it as spam or block it altogether.
- The key published in the DNS is what the recipient’s server uses to authenticate your DKIM signature. If it’s not published right or there’s a mistake, their server will either mark your email as untrustworthy or reject it.
- If your DKIM key is shorter than 1024 bits, be prepared for your emails to be intercepted by threat actors. Email providers will flag any key of less than 2048 bits, primarily because emails with shorter DKIM keys are not secure enough.
- In case your email is modified during an auto-forwarding, the DKIM signature is bound to be broken. This broken DKIM signature is a telltale sign for the receiving server that your email has been tampered with, which then treats it as a threat, therefore affecting deliverability.
Fixing an invalid DKIM signature
Now that you know what are the potential reasons your DKIM signature could be broken or invalid, it’s time to learn how to fix it.
- The first step is to run the DKIM record through a checker or validator to detect any mistakes. The checker or validator will let you know whether the record is correctly published, whether there are any syntax problems, or whether the public key is available.
- If the validator comes across any such issues, you’ll need to go into your DNS settings to correct them. While doing so, make sure that you enter the correct values and address all the pain points that were flagged by the tool.
- Once done, all you have to do is save the changes and wait for some time for them to reflect.
We understand that configuring DKIM can be tricky, especially when there are so many complexities involved. The good news, though, is that it’s not rocket science either. Moreover, the ‘invalid DKIM signature’ error is more common than you think. But with the right tools and a bit of attention to detail, you can rest assured that your DKIM configuration is on point and your emails are secure.
