Have you ever received an email from a trusted source that turned out to be a malicious phishing scam?
It's like getting a letter that looks like it's from your bank, but it's a clever forgery trying to dupe you into giving up your personal information. That's where DomainKeys Identified Mail (DKIM) comes in.
Like a holographic seal on a credit card or a watermark on currency, DKIM is an email authentication protocol that verifies the sender's legitimacy and ensures the message has not been tampered with.
Securing your email communication with the help of Domain-Based Message Authentication, Reporting, and Conformance (DMARC) software helps block suspicious email activity and increase security. DMARC software helps authenticate emails against DKIM and sender-policy framework (SPF) standards.
DKIM is an email authentication method designed to enhance email security and help prevent email spoofing and phishing attacks. It enables the sender to sign an email using a private cryptographic key, adding a unique DKIM signature to the email's header. The recipient's email server then verifies the signature by looking up the sender's public key via the Domain Name System (DNS).
This process helps ensure the email's authenticity and integrity, as the signature proves that the email has not been tampered with during transit and originates from an IP address associated with the claimed sender.
DKIM is an essential part of modern email infrastructure. When coupled with other authentication methods like SPF and DMARC, it helps ensure a safer and more trustworthy email experience.
DKIM is an important email authentication method that provides multiple benefits related to email security to its end users.
In summary, DKIM is crucial because it helps ensure email authenticity and integrity while improving deliverability for legitimate senders and reducing the effectiveness of spam and phishing attacks.
DKIM uses cryptographic digital signatures to authenticate the sender's domain and ensure email integrity. A cryptographic digital signature is used to verify data authenticity. It works by signing outgoing email messages with a digital signature verified by the recipient's email server. Additionally, DKIM validates that the message has yet to be modified in transit.
Here's a step-by-step overview of how DKIM works:
By leveraging the combination of cryptographic hashing and public-private key encryption, DKIM provides a reliable way to authenticate the sender's domain and maintain email integrity.
It is important to note that users must include DKIM in conjunction with other email authentication methods to enhance overall email security and ensure trustworthy email communication by providing a way to verify the authenticity of email messages.
To set up DKIM for your custom domain, you can follow these general steps:
It's important to note that the specific steps and commands may vary depending on your email service provider and software/platform. For more detailed instructions, refer to the documentation provided by your provider or follow a specific tutorial.
A DKIM record is a TXT record created in the sender's domain's DNS. It serves as a public key counterpart to the private key used for generating DKIM signatures in email headers.
The main purpose of a DKIM record is to enable the recipient's email system to retrieve the sender's public key for decrypting and verifying DKIM signatures in received emails.
By having the DKIM record available in the sender's DNS, the recipient's email systems can perform DKIM checks and verify the authenticity and integrity of received emails, ultimately helping to improve email security and reduce email spoofing and phishing attacks.
Setting up a DKIM record largely depends on the email system and DNS provider you're using. However, the general steps are as follows:
Remember, the specific steps and tools might vary depending on your email system (like Office 365, Google Workspace, Microsoft, etc.) and your DNS provider. If you encounter any issues, it would be best to refer to the specific documentation of your system or contact their support.
A DKIM record check is a process that verifies whether a domain has a correct DKIM record set up. The purpose of the DKIM record is to store a public key used to verify the messages signed by the private key. Most online tools that offer DKIM record checks verify the domain name, the public key's syntax, and the DNS entries set up on the corresponding domains.
One example of a DKIM record check tool provided by MxToolbox performs DKIM testing against a domain name and selector for a valid published DKIM key record. It tests the domain-level digital signature authentication framework for email by allowing a signing domain to assert responsibility for a message in transit.
Overall, running a DKIM record check can help identify potential issues in your email authentication setup and help ensure that your messages are delivered to recipients securely. Secure email gateway software can further be used to filter spam emails and prevent malicious spammers from attacking the end users.
A DKIM selector is a string used by the outgoing mail server to locate the private key to sign an email message and by the receiving mail server to locate the public key in the DNS to verify the integrity of the email message.
The selector is part of a domain's DKIM record and is specified by the "s=" tag in the DKIM-Signature header field. The selector helps to support multiple DKIM key records for a single domain and is an arbitrary string that helps with the DKIM Public Key identification process.
DKIM uses a pair of cryptographic keys, one public and one private, to sign outgoing email messages. The public key is published in the organization's DNS records as a TXT record, and the private key is kept secret by the sender.
When an email message is sent using DKIM, it includes a digital signature in the message header. The receiving email server can use the sender's public DKIM key to verify the signature. If the signature doesn't match, it means the message was modified during transmission or wasn't sent by a legitimate sender.
In more technical terms, DKIM uses a hash function to produce an encrypted digest of specific parts of the email message body and header, which are then signed using the sender's private key. The digest and the sender's domain name are then added to the message header as a digital signature.
The receiving server can retrieve the public key for the sender's domain from the DNS records and use it to verify the digital signature. If the signature matches the digest, the email message is authenticated and trustworthy.
By verifying the DKIM signature of incoming emails, organizations can ensure that emails sent by their domain are delivered successfully and prevent email phishing and spoofing attacks.
A DKIM signature is a unique, encrypted string of characters created by the sender's email system during the DKIM email authentication process. The signature's main function is to verify the sender's domain and ensure the email's integrity during transit between the sender and the recipient.
When an email is sent using DKIM, the sender's email server attaches a digital signature to the message. This signature is generated using an encryption algorithm and a private key that is unique to the sender's domain. The public key corresponding to this private key is stored as a DNS record.
When the email is received by the recipient's email server, it checks the DKIM signature by retrieving the corresponding public key from the sender's DNS record. The server then uses this public key to decrypt the signature and verify its authenticity. If the signature matches, it means that the email has not been altered or tampered with since it was sent. DKIM signatures also provide information about the domain that sent the email.
In summary, a DKIM signature is a digital signature that verifies the authenticity and integrity of an email message. It helps prevent email tampering and ensures that the email is indeed sent by the claimed domain.
It's important to note that the specific commands and libraries for verifying DKIM signatures may vary depending on the programming language and platform you use. You can find libraries and tools for verifying DKIM signatures, such as DKIMpy for Python and DKIMVerifier for .NET.
Additionally, it's recommended to check other email authentication mechanisms, such as SPF and DMARC, to provide a more comprehensive email security approach.
DKIM and SPF are two types of email authentication protocols.
DKIM adds a digital signature to an email to verify that the message was not only sent from the purported domain but also that the message itself was not altered during transit.
SPF, on the other hand, works by verifying the sending mail server against a list of authorized sending servers for a given domain. If the server is not authorized, the receiving server has a few options for handling the questionable email.
DMARC, on the other hand, is used to take advantage of the verification process performed by DKIM (as well as SPF) and allows email senders to instruct email receivers on how to handle messages that fail authentication. Specifically, DMARC policies define how email receivers should evaluate incoming messages against established authentication standards, such as DKIM and SPF, and what actions to take if an email fails these checks.
So while DKIM is primarily used for sender authentication, DMARC provides an additional layer of security by enabling domain owners to specify how receivers should handle email that fails authentication. By deploying both DKIM and DMARC, domain owners can significantly reduce the risk that their domain will be used for phishing and spoofing attacks, and improve email deliverability.
DMARC is a technical specification and email authentication protocol designed to give email domain owners the ability to protect their domains from unauthorized use like email phishing and spoofing attacks.
To enable DMARC, domain owners publish a DMARC policy in their DNS records that indicate which authentication methods (such as SPF and/or DKIM) should be used to verify incoming email messages, and how email receivers should handle messages that don't pass the verification checks.
There are various DMARC software solutions available, both paid and free, that help organizations implement DMARC policies and provide detailed reporting on email authenticity across various email providers.
*These are the top 5 DMARC software solutions from G2’s Summer 2023 Grid® Report.
A. Yes. Users can have multiple DKIM records in the DNS. Every DKIM key is associated with a different DKIM selector added to the signature. This allows the receiver to understand which keys are used for validation.
A. Gmail Simple Mail Transfer Protocol (SMTP) or Gappssmtp is an email-sending protocol provided by Google. It is the standard protocol for email sharing over the internet. Gappssmtp helps configure email applications or server settings to ensure emails can be sent through Gmail servers while preserving the “sent from” address as the sender's domain.
Gappssmtp ensures safety and reliability without the need for a separate server. Set up the server with the following:
SMTP Server: smtp.gmail.com SMTP Port: 587 Encryption: TLS (Transport Layer Security)
When composing an email, you would set the 'From' address as your own domain (for example, email@example.com). When the recipient receives the email, it will appear as if it was sent directly from your domain, despite being sent through Gmail's servers.
A. No. A certificate isn’t required to run DKIM. It gives users a quick way to create, set up, or destroy keys.
A. After a DKIM has been added, it must be validated with an online DKIM analyzer. There are various free DKIM analyzers available online. Another method of checking validation is sending a test email to Gmail or Yahoo to verify whether the email arrives with a DKIM signature.
To do so, expand the email header by clicking on the triangle icon below the sender’s name. If the domain name appears for “sent-by” and “signed-by”, the email was configured correctly.
A. DKIM acts more as a mediator to ensure that the email hasn’t been tampered with during the transit to the recipient server. It doesn’t ensure end-to-end encryption.
A. A typical DKIM header looks like this:
DKIM-Signature: v=1; a=rsa-sha256;
Let's break down the parts of the DKIM header:
Please note that the actual DKIM header may vary depending on the specific email service or software being used.
DKIM is one piece of the puzzle. It verifies the sender's domain and the email's integrity via cryptographic signatures, helping combat email forgery, spoofing, and tampering. By adopting DKIM and other such email security measures, you are on your way forward to a secure, trustworthy, and fruitful email communication and authentication environment.
Slight changes to your email deliverability practices can bring exceptional results to your email strategies. Learn more!
Tanuja Bahirat is a Content Marketing Specialist at G2. She has previously written for the ed-tech industry and currently specializes in Data De-Identification, DDoS protection, mobile data security, cloud directory services, DNS security, runtime application self-protection, and network security policy management among other security categories to provide valuable information to readers. When she's not busy writing, she can be found attending local concerts, exploring cafes, trying her hand at baking, or binge watching series.
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