Email is an effective tool for business and personal communication in the digital age. But with the increase in the frequency of phishing scams and email fraud, businesses need to ensure that their email communications are secure and trustworthy. This is where email authentication technology can help.
The Importance of DKIM Email Authentication
DKIM (DomainKeys Identified Mail) is an email authentication method that confirms that an email comes from the intended sender and that its contents have not been altered in transit. DKIM helps prove the authenticity of outgoing emails through digital signatures.
Additionally, DKIM is important for the DMARC authentication protocol, which is used to prevent malicious senders from distributing doctored or fraudulent email communications on behalf of legitimate businesses.
How does DKIM work?
Like SPF and DMARC, the mechanics of the DKIM email authentication protocol involve creating a DNS record for your domain. The DKIM record contains the public key that email recipients use to verify the DKIM signature of an email.
The DKIM authentication protocol process consists of the following stages:
1. Create a DKIM key.
The sender creates a pair of cryptographic keys: a private key and a public key. The private key is stored on the sender’s email server and used to create the DKIM signature. The public key is published as a grenada email list 18731 contact leads record and used by email recipients to verify the DKIM signature.
DKIM records are published in the domain’s DNS in the following format:
selector._domainkey.example.com IN TXT “v=DKIM1; k=rsa; p=publickey”
Where:
- Selector — Indicates the selector name of the DKIM key. The selector is the part of the DKIM record that allows Reasons why DKIM fails: identification of the correct public key for DKIM signature verification. Using the selector, the sending domain can use multiple public keys or key rotation for different senders;
- _domainkey — predefined suffix for all DKIM signatures;
- example.com — the sender’s domain name;
- v=DKIM1 — version of the DKIM protocol;
- k=rsa — encryption algorithm;
- p=publickey — The encrypted public key.
2. Add a DKIM signature to the email.
The sending server uses a private key to create a digital signature over different parts of the message header and body. The signature is added to the message as a header called DKIM-Signature.
Example of a DKIM signature header:
DKIM signature: v=1; a=rsa-sha256; c=relax/relax; d=example.com;
s=my selector; h=sender:recipient:subject: Reasons why DKIM fails: date:message-id; bh=base64_body_hash;
b=base64_signature;
3. Send and receive emails.
DKIM signed emails are sent to recipients via email service providers or SMTP servers.
The recipient’s server looks up the DKIM-Signature header and uses the selector indicated in the signature ( s=myselector in the example above ) to get the public key from the sender’s domain DNS record.
4. Verify the DKIM signature.
The recipient’s server uses the public key to verify the DKIM signature. It does this by encrypting the same components in the message with the public key. The server then matches the encrypted result (the hash string) with the decrypted sender hash. If the two strings america cell phone number library authentication passes, confirming that the email was indeed sent from the specified domain and was not altered in transit.
Depending on the success or failure of the DKIM authentication verification, the recipient’s server returns the following results:
- Pass: The DKIM signature is valid Reasons why DKIM fails: and the verification is successful.
- Failed: The DKIM signature is missing or invalid.
- Temperror: A temporary authentication error (for example, due to an unavailable DNS server).
- Permerror: A permanent validation error (for example, due to incorrect DNS record syntax or missing required header fields).
Why does DKIM Reasons why DKIM fails: fail?
DKIM Failed is a status where the DKIM authentication check for an email fails due to various issues. The most common reasons for DKIM Failed are:
1. Missing DKIM configuration.
Disabled DKIM signing in your email mobile list provider and missing public and private keys required for DKIM authentication can cause DKIM to fail when the mail server tries to verify the authenticity of the email.
2. DNS settings are incorrect.
Invalid public keys or syntax errors in the DKIM records published in your domain’s DNS will cause DKIM authentication to fail.
3. Missing public key.
If a message is signed with a DKIM signature, but the public key is not published in DNS, the receiving server cannot perform DKIM verification. This situation typically results in a DKIM failure with a ” dkim=fail (no signing key)” server response.
4. DNS server Reasons why DKIM fails: problem.
DKIM uses the Domain Name System (DNS), where public keys used for email authentication are stored. DNS availability issues can cause DKIM failures because the receiving server may not be able to retrieve the DKIM public key from the DKIM DNS record.
5. Mail server problem.
Configuration or functionality issues with the receiving server can sometimes cause DKIM failures. The server might not be able to retrieve the DKIM record from DNS or create the hash to verify the signature. In this case, it returns a temporary error for the DKIM authentication test.
6. Message modification.
DKIM failures occur when a message is altered in transit. DKIM validation typically returns the following response:
dkim=fail (signature not verified)
dkim=fail (DKIM signature body hash not verified)
In this case, even if a single character is changed, the hash value received after encrypting the message with the public key will be different from the hash value delivered by the sending server.
Failure to verify the DKIM signature increases the likelihood that an attacker can alter the message. Also, as the message bounces between servers, the content of the email could be altered by the intermediate server.
7. Expired DKIM key.
Both the DKIM public key and private key have expiration dates. When either of them expires, the DKIM signature cannot be verified and the DKIM generation fails.
8. Normalization algorithm.
DKIM canonicalization is the process of converting the header and body of an email message into a standardized form before applying the DKIM signature. This ensures that the data is in a consistent format for verification.
