For small to medium-sized business owners in today’s digital landscape, protecting against cyber threats is critical to maintaining a reputable, secure operation. With email remaining one of the most common entry points for cyber-attacks, it’s vital that your Managed Service Provider (MSP) deploys effective security measures. At Trichromic LLP, we’re committed to safeguarding our clients by implementing email authentication protocols like SPF, DKIM, ARC, and DMARC. These tools help stop spam, phishing, and spoofing attempts that can put your business, employees, and customers at risk.
Understanding Email Authentication and Its Importance
The protocols SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), ARC (Authenticated Received Chain), and DMARC (Domain-based Message Authentication, Reporting, and Conformance) work together to verify the identity of the sender and ensure that messages have not been altered during transmission. Here’s a quick rundown of what each protocol does:
1. SPF: Checks whether the server sending an email is authorized by the domain’s owner, reducing the chance of fraudulent emails pretending to be from your domain.
2. DKIM: Adds a cryptographic signature to each email, ensuring that the message hasn’t been tampered with en route to the recipient.
3. DMARC: Provides your domain with a set of policies for handling unauthenticated emails. DMARC combines SPF and DKIM results and lets you specify how failed messages should be handled (quarantined or rejected) and receive reports on these failures.
4. ARC: Ensures the continuity of authentication for emails that are forwarded or relayed through third-party services. Without ARC, emails forwarded through services like mailing lists may fail authentication checks, leading to unnecessary rejections.
When used together, these protocols provide a layered defense against email-based cyber threats. They establish your legitimacy as a sender, ensure your messages reach their intended recipients, and guard against potentially costly and reputation-damaging spoofing attacks. For small businesses without these protections, the risks include email fraud, data breaches, financial loss, and reputational harm.
Beyond the Basics: BIMI and TLS-RPT for Brand Trust and Reporting
In addition to SPF, DKIM, DMARC, and ARC, two more protocols, BIMI (Brand Indicators for Message Identification) and TLS-RPT (TLS Reporting), offer additional security and branding benefits.
1. BIMI: This protocol allows you to display your company’s logo next to your emails in your recipients’ inboxes, boosting brand recognition and building trust. When customers see your logo, they know the email is genuinely from you, enhancing engagement and security. However, BIMI requires a properly configured DMARC policy and often a Verified Mark Certificate (VMC), making it more complex and potentially costly to implement.
2. TLS-RPT: This protocol provides transparency about any issues with Transport Layer Security (TLS) encryption, which keeps your messages secure while in transit. If a recipient’s server experiences a problem establishing a secure connection, TLS-RPT sends a report to your MSP, enabling timely responses to potential vulnerabilities. While it adds an extra layer of security, implementing TLS-RPT requires ongoing monitoring and maintenance, which can be challenging for smaller companies.
Why These Protocols Are Challenging for Smaller Businesses
For small business owners, time, budget, and technical expertise are limited resources. BIMI and TLS-RPT, while valuable, can be challenging for smaller companies to implement because they require technical expertise, ongoing monitoring, and sometimes additional costs, such as obtaining a Verified Mark Certificate for BIMI. This is where an experienced MSP like Trichromic LLP can bridge the gap, handling the complexities and ensuring these protocols are configured to your needs and budget.
The Role of Your MSP in Keeping Your Business Safe
As an MSP specialising in small to medium-sized businesses, Trichromic LLP has the experience and tools to implement these critical email security measures efficiently and affordably. Our goal is to help you enhance email security, protect your brand reputation, and maintain customer trust without requiring a large, in-house IT team.
By partnering with Trichromic LLP, you can have peace of mind knowing that your email systems are safeguarded against cyber threats, and you’re taking proactive steps to protect your business and brand. Let us help you navigate the complexities of email security and create a more secure, trustworthy communication channel with your customers.
For more information on how Trichromic LLP can support your email security needs, contact us today. Together, we’ll ensure your emails are safe, secure, and ready to build lasting customer trust.
If you want to know more, keep reading.
1. DMARC (Domain-based Message Authentication, Reporting, and Conformance)
Purpose: DMARC is an email authentication protocol that builds on SPF and DKIM to help prevent email spoofing. It allows domain owners to set policies on how email providers should handle emails that fail SPF or DKIM checks.
How it Works: It uses DNS records to specify whether an email should be delivered, quarantined, or rejected based on SPF and DKIM validation results. It also allows for reporting of email messages sent using a domain.
Benefits: Helps prevent phishing and protects against email spoofing by ensuring that only legitimate emails are delivered under a domain’s identity.
2. SPF (Sender Policy Framework)
Purpose: SPF is an email validation system designed to prevent email spoofing by specifying which mail servers are permitted to send email on behalf of a domain.
How it Works: Domain owners publish SPF records in the DNS. When an email server receives a message, it checks the SPF record to verify that the sending server’s IP address is authorized to send emails for that domain.
Benefits: Reduces spam and spoofing by helping email providers verify the legitimacy of the email sender’s IP address.
3. DKIM (DomainKeys Identified Mail)
Purpose: DKIM adds a cryptographic signature to emails, allowing the recipient’s email server to verify that the message was indeed sent and authorized by the owner of the sending domain.
How it Works: The sender’s mail server generates a cryptographic signature for each outgoing email, which is added to the email’s header. The recipient’s server retrieves the public key from the sender’s DNS and verifies the signature.
Benefits: Protects against tampering during transmission and confirms the authenticity of the sender’s domain.
4. BIMI (Brand Indicators for Message Identification)
Purpose: BIMI enables brands to display their logos next to authenticated emails in recipient inboxes, enhancing brand recognition and trust.
How it Works: BIMI relies on a properly configured DMARC policy with a “quarantine” or “reject” setting. It also often requires a Verified Mark Certificate (VMC) to authenticate the brand logo. When the email is authenticated, the brand logo appears in the inbox.
Benefits: Increases brand visibility and recipient trust, particularly when recipients see a recognized logo in their inbox.
5. TLS-RPT (TLS Reporting)
Purpose: TLS-RPT (Transport Layer Security Reporting) is used to enable reporting of issues regarding email security using TLS encryption.
How it Works: Domain owners can publish a TLS-RPT DNS record specifying where reports should be sent. If a receiving server encounters issues establishing a secure (TLS) connection, it sends a report to the specified address.
Benefits: Provides insight into any failed TLS connections, helping improve email security configurations and identify potential issues.
These protocols work together to help authenticate email, protect against spoofing, ensure message integrity, and provide reporting and visibility into any security issues.
Now for a more technical explanation why a message may potentially be marked/blocked as spam.
When the “MAIL FROM” address in the SMTP envelope differs from the “From:” address in the email header, it can trigger various email security/authentication mechanisms, especially with modern anti-spam and anti-phishing technologies such as SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting & Conformance). Let’s consider what happens in each of these contexts:
1. Sender Policy Framework (SPF)
SPF is a mechanism that validates the IP address of the server sending the email against the domain’s published SPF records. SPF works by checking the “MAIL FROM” (envelope sender) address to see if the server sending the email is authorized to send on behalf of that domain.
If the “MAIL FROM” domain is different from the domain in the “From:” header, and the IP address of the server sending the email is not authorized to send on behalf of the “MAIL FROM” domain, the SPF check may fail.
SPF does not directly verify the “From:” header, so a discrepancy between “MAIL FROM” and “From:” will not directly impact SPF, but the IP address must be authorized for the “MAIL FROM” domain.
2. DomainKeys Identified Mail (DKIM)
DKIM allows the sending domain to sign certain headers and the body of the email using a private key. The recipient’s mail server can then verify the signature using the public key published in DNS records.
DKIM typically signs headers like “From:”, “Subject:”, and “Date:”, among others.
The discrepancy between the “MAIL FROM” and the “From:” address may or may not affect DKIM verification, depending on which headers are included in the DKIM signature. However, the “From:” address is commonly included to ensure authenticity.
If the DKIM signature does not match the “From:” header or if the server doesn’t properly sign the email, DKIM verification will fail.
3. Domain-based Message Authentication, Reporting & Conformance (DMARC)
DMARC builds upon SPF and DKIM to provide additional protection, and it directly addresses scenarios where the “MAIL FROM” and “From:” addresses differ.
DMARC policy requires that either SPF or DKIM passes validation and that the domain in the “From:” address aligns with the domain used in SPF or DKIM.
There are two types of alignment:
Strict Alignment: The domain in the “From:” header must exactly match the domain used for SPF or DKIM validation.
Relaxed Alignment: The domains must share the same organizational domain (e.g., user@sub.example.com aligns with user@example.com).
If the “From:” address is different from the “MAIL FROM” domain, the alignment may fail, and if both SPF and DKIM fail or misalign, the email may be marked as spam or rejected depending on the DMARC policy (none, quarantine, reject) set by the domain owner.
4. Impact on Spam Filtering
Modern spam filters use a combination of techniques, including SPF, DKIM, DMARC, header analysis, and heuristics. When the “MAIL FROM” address and “From:” header are different, this is often viewed as suspicious behavior, as it may indicate email spoofing or phishing.
Some spam filters may consider the email suspicious if the “MAIL FROM” address does not match the “From:” header, especially if the sender domains are unrelated.
Emails with mismatched addresses are more likely to be flagged as spam or phishing unless explicitly trusted by the recipient or whitelisted.
Example Scenarios
If MAIL FROM is <mailer@service.com> but the From: header says <noreply@bank.com>, this discrepancy could raise a red flag, especially if service.com is not authorized by bank.com through SPF, or if DKIM signatures don’t align.
If SPF passes but DKIM fails, and there is no alignment between the “From:” and “MAIL FROM” domains, DMARC could cause the email to be rejected or quarantined.
Summary
SPF checks the “MAIL FROM” address, ensuring that the sending server is authorized.
DKIM signs the email headers and body to ensure authenticity.
DMARC ensures alignment between the “From:” header and either SPF or DKIM. If alignment fails, the email could be rejected or flagged as spam.
When the “MAIL FROM” in the envelope differs from the “From:” header, this discrepancy can create problems with SPF, DKIM, and DMARC alignment, leading to delivery issues such as the email being flagged as spam, quarantined, or even rejected. To avoid these problems, it’s best to ensure consistency between the SMTP envelope and the email headers, especially with modern email authentication standards in place.
For more information on how Trichromic LLP can support your email security needs, contact us today by calling 02033270310. Together, we’ll ensure your emails are safe, secure, and ready to build lasting customer trust.