How to Securely Configure Emails

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At Careful Security, we frequently experience organizations experiencing email delivery issues. To troubleshoot, it's essential to understand and implement the three cornerstones of email authentication: DMARC, DKIM, and SPF, to protect your domain's emails and to provide assurance to those they are sent to. Let's delve into three critical acronyms every business should include in its cybersecurity strategy?

SPF?

SPF (Sender Policy Framework) is your first line of defense acting as a public directory of your Server IP addresses authorized to send emails on behalf of your domain. A SPF record is a type of DNS?TXT record?that lists all the servers authorized to send emails from a particular domain. When an email arrives, the receiving server checks this list, and if the sender's IP isn't listed, the email could be untrustworthy.?

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How to test if you have a valid SPF record??

To test the validity of your SPF record, you can use online SPF validation tools. These tools simulate sending servers and check if your domain's SPF record is found and correctly formulated. It's like running a fire drill to ensure all safety measures work as intended.?

What happens when we don’t have a SPF record??

Lacking an SPF record is akin to having an unlisted number in the phone book; anyone can claim they're calling from your home. Without an SPF record, there's no way to verify if emails are truly from your domain, leaving the door open for spammers to impersonate you, potentially leading to your domain being blacklisted.?

How to add a SPF record??

Adding an SPF record involves creating a TXT record in your domain's DNS settings that specifies which mail servers are permitted to send emails on behalf of your domain. It's similar to issuing a list of authorized personnel to security staff. You'll need to list all the IP addresses that are sanctioned to send mail from your domain, ensuring that only legitimate servers are recognized.?

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DKIM?

DKIM (DomainKeys Identified Mail) provides a layer of authenticity to your emails, providing a unique signature validating an email’s domain. A DKIM record is a specialized DNS TXT record that stores the public key used to verify an email's authenticity. It uses a pair of cryptographic keys (public and private) to verify that an email genuinely comes from your domain and remains unaltered in transit. DKIM helps organizations take responsibility for their email domain authenticity and aids in preventing email spoofing and phishing.?

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What happens when we don’t have a DKIM record??

Without a DKIM record, your domain lacks a crucial layer of authentication, much like a passport without a signature. Emails sent from your domain are more likely to be questioned by receiving email servers and could end up in spam folders or be rejected entirely. This absence can damage your domain's credibility and diminish the trust in your email communications.?

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How to add a DKIM record??

To add a DKIM record, you'll need to generate a pair of keys: a private key that remains on your email server and a public key that will be published in your DNS. The process is akin to creating a seal that uniquely identifies your domain. Once you have your keys:?

• The private key is configured on your email server, enabling it to sign outgoing emails automatically.?
• The public key is added to your DNS records as a TXT record, allowing receiving servers to verify the signatures of emails claiming to be from your domain.?

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DMARC?

DMARC (Domain-based Message Authentication, Reporting, and Conformance) records are also stored in DNS as?TXT records. DMARC leverages SPF and DKIM to provide an additional layer of security by specifying how mail receivers should handle messages that don't pass SPF or DKIM checks. Should they be blocked or just monitored carefully? DMARC also provides reporting back to the domain owner about messages that pass and fail DMARC evaluation, offering visibility into the health of a business's email ecosystem.?

DMARC acts as a policy maker and uses SPF and DKIM to determine the legitimacy of an email and instructs the receiving server on what to do with emails that fail these checks. It can tell servers to mark them as spam, reject them outright, or let them through while flagging them for further inspection.?

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What happens when we don’t have a DMARC record??

Without a DMARC record; there's nothing to enforce order. This lack of enforcement can lead to:?

• Unmonitored email spoofing: Your domain could be used in phishing attacks without your knowledge, as there's no mechanism to report or monitor such activities.?
• Reduced email deliverability: Emails from your domain may be more frequently rejected or marked as spam by recipient email servers, as there's no policy instructing them to trust your emails.?
• Damaged domain reputation: Continuous spoofing and spam flagging can tarnish your domain's reputation, potentially leading to blacklisting by email providers.?

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How to add a DMARC record??

Here's how to establish a DMARC policy for your domain:?

1. Determine your policy: Decide what you want receiving servers to do with emails that fail SPF and DKIM checks—none (monitor), quarantine (mark as spam), or reject (block).?

1. Create the DMARC record: Write your DMARC policy in the correct format, which usually starts with v=DMARC1; p=none; rua=mailto:[email protected], where p=none is the policy, and rua is the reporting URL for aggregate reports.?

1. Publish the DMARC record: Add the DMARC record to your DNS as a TXT record. This allows receiving email servers to find and apply your DMARC policy when processing emails from your domain.?

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The Importance of Correct Configuration ?

Without proper setup of these three protocols, your domain is an open door to spammers and impersonators. Improperly configured SPF, DKIM, and DMARC records can lead to emails being flagged as spam or not delivered, damaging your domain's reputation and communication channels. In addition, domains must often implement DMARC even if they don’t send email, to prevent their domain from being exploited by spammers.?

Insights and Recommendations?

• SPF, DKIM, and DMARC records need to be regularly reviewed to ensure they are up-to-date and aligned with your current email-sending practices.?
• Start with a monitoring policy of (p=none) to monitor and then move towards a reject policy (p=reject) to prevent unauthorized emails from being delivered.?
• Follow DMARC reports to assist with analyzing trends and detecting anomalies in email traffic?

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At Careful Security, we ensure that your SPF, DKIM, and DMARC records are not just present but configured optimally for your business's unique needs. Reach out for a consultation, and let's secure your business’s communication channels with precision and foresight with proactive cybersecurity measures. ?

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