SPF, DKIM & DMARC – simple terms
- SPF (Sender Policy Framework):
- Think of SPF like a whitelist for your email server. It’s a way for a company to say, “These are the only servers that are allowed to send emails claiming to be from us.”
- When an email is received, the recipient’s email server checks if the sending server is on this list. If it’s not, the email might be marked as suspicious or rejected.
- SPF helps prevent scammers from pretending to be you when they send emails.
- DKIM (DomainKeys Identified Mail):
- DKIM is like putting a digital seal on your email.
- When you send an email, your server seals it with a special signature. When the recipient gets the email, their server checks this seal to make sure it’s really from you and hasn’t been tampered with.
- This ensures that the email hasn’t been messed with during its journey and truly comes from the claimed sender.
- DMARC (Domain-based Message Authentication, Reporting, and Conformance):
- DMARC is like setting rules for what to do with emails that don’t pass SPF or DKIM checks.
- It allows you to say, “If an email fails these checks, don’t deliver it, or put it in a special folder.”
- It also gives you reports on how your email is being used, so you can see if someone is trying to impersonate you or if there are any issues with your email setup.
In simpler terms, these three things work together to make sure emails are really from who they say they’re from, haven’t been changed along the way, and give you control over what happens to emails that don’t meet these standards. It’s like adding locks, seals, and security cameras to your email to keep it safe from scammers.
SPF, DKIM & DMARC – more technical terms
SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting, and Conformance) are all important email authentication protocols designed to combat email spoofing, phishing, and other forms of email fraud. Each protocol serves a specific purpose, and together they provide a layered approach to ensuring the integrity and authenticity of email messages. Here’s a brief explanation of each:
- SPF (Sender Policy Framework): SPF is a DNS-based authentication protocol that allows a domain owner to specify which IP addresses are authorized to send email on behalf of their domain. When an email is received, the recipient’s email server can check the SPF record of the sender’s domain to verify if the sending server is authorized to send emails on behalf of that domain. If the sending server’s IP address is not listed in the SPF record, the email may be marked as suspicious or rejected outright. SPF helps prevent email spoofing by verifying the sending server’s identity.
- DKIM (DomainKeys Identified Mail): DKIM is another email authentication method that involves cryptographic signatures. When an email is sent, the sender’s email server generates a unique digital signature using a private key associated with the sending domain. This signature is added to the email’s header. Upon receipt, the recipient’s email server retrieves the public key from the sender’s DNS records and uses it to verify the signature. If the signature is valid, it confirms that the email has not been tampered with in transit and that it originated from the claimed sender. DKIM helps ensure email integrity and prevents tampering and spoofing.
- DMARC (Domain-based Message Authentication, Reporting, and Conformance): DMARC builds on SPF and DKIM to provide domain owners with greater control and visibility over their email authentication practices. DMARC allows domain owners to specify policies for how email servers should handle messages that fail SPF and/or DKIM checks. This includes options to quarantine or reject suspicious emails and instructions for how to handle messages that pass authentication checks but fail other criteria, such as being sent from unauthorized sources. DMARC also enables domain owners to receive reports on email authentication failures, providing valuable insights into potential phishing attempts and unauthorized use of their domain.
In summary, SPF, DKIM, and DMARC work together to authenticate the sender’s identity, verify the integrity of email messages, and provide mechanisms for domain owners to enforce policies and receive feedback on email authentication practices. Implementing these protocols helps protect against email fraud, phishing attacks, and domain impersonation, ultimately enhancing email security and trustworthiness.
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Zone files
Zone files are like maps that tell the internet where to find different parts of a domain, like its website or email servers. They contain records that match domain names to specific IP addresses or other important information, helping computers navigate and connect to the right places online.
SPF, DKIM & DMARC – more luddite terms
SPF
Imagine you’re sending a letter through the postal service, but instead of writing your name and address on the envelope, you’re using a special code. This code tells the postal service who you are and whether they should trust the letter is really from you.
SPF, or Sender Policy Framework, is like that code for emails. It’s a way for email servers to check if an email claiming to be from your domain (like yourwebsite.com) is actually sent from servers that are allowed to send emails for your domain.
Think of it as a security guard at the entrance of a building. When someone tries to enter, the guard checks their ID to make sure they’re allowed inside. Similarly, SPF helps email servers verify the identity of emails by checking if they’re coming from authorized servers.
If an email doesn’t pass the SPF check, it’s like the security guard denying entry to someone with a fake ID – the email might get marked as suspicious or even rejected altogether to protect against spam and phishing attempts.
In simple terms, SPF helps ensure that emails from your domain are genuine and not imposters, making the internet a safer place for everyone.
problem: multiple SPF records
Imagine you’re sending a letter to someone, and you’re providing two contradictory sets of instructions on how the recipient should handle your mail. One instruction says, “Leave the letter at the doorstep,” while the other says, “Put the letter directly into the mailbox.” Now, the person receiving the letter doesn’t know which instruction to follow, and confusion arises.
Similarly, in the world of email, SPF records are like instructions for mail servers on how to handle emails sent from your domain. If there are multiple SPF records, they might give conflicting instructions on which servers are authorized to send emails on behalf of your domain. This leads to confusion for receiving mail servers, which may result in legitimate emails being marked as spam or rejected altogether.
To avoid this confusion, it’s best to have a single SPF record that clearly specifies the rules for email authentication. This helps ensure that receiving mail servers can properly authenticate emails from your domain and deliver them to the recipient’s inbox without issues.