DMARC for Multiple Domains: The MSP’s Guide

Managing DMARC for multiple domains is a growing challenge for Managed Service Providers (MSPs). With clients relying on MSPs to secure email communications, ensuring proper implementation of DMARC across many domains is essential to prevent phishing, spoofing, and business email compromise. 

A scalable strategy allows MSPs to unify multi-domain DMARC policies, automate monitoring, and resolve domain-specific issues efficiently. This guide explores how MSPs can strengthen email authentication at scale, overcome common challenges, and deliver stronger MSP email security through multi-domain DMARC management.

Why DMARC Is Important for MSPs

DMARC has many benefits for MSPs. It helps: 

Protect Client Domains from Phishing and Spoofing

DMARC stops hackers from impersonating a client’s domain. When you enforce a p=reject policy, you significantly reduce the chance of malicious emails reaching inboxes. This can help protect your client’s brand and their customers.

Boost Email Deliverability

Major mailbox providers like Google and Yahoo now require strong email authentication. A properly configured DMARC record signals to receiving servers that an email is legitimate. 

Maintain Trust and Compliance for Clients

Many industries have compliance standards (GDPR, HIPAA, PCI DSS)  that require strict data security measures. When you have DMARC in place, you increase your chances of compliance. Moreover, email service providers like Google, Yahoo, Microsoft, and Apple Mail now require DMARC for high-volume email senders. 

Risks of Unmanaged DMARC

With no DMARC, a domain is an open invitation for abuse. Without DMARC: 

• An MSP’s clients are vulnerable to brand impersonation, data breaches, and financial loss. 
• This can lead to reputational damage, customer churn, and potential legal liabilities.
• These risks can directly impact the MSP’s relationship with the client.

What Challenges Do MSPs Face in Multi-Domain DMARC Management? 

Managing multi-domain DMARC can be very challenging for MSPs. The complexity grows exponentially with each new client.

An MSP might be responsible for 50, 100, or more distinct domains. Each of these may have its own set of authorized sending services (e.g., Microsoft 365, Mailchimp, Salesforce). Manually tracking and updating DNS records for each one is a logistical nightmare.

This leads to the next challenge: the complexity of SPF and DKIM alignment. For DMARC to pass, the domain in the “From” header must align with the domains specified in SPF and DKIM. 

Each new third-party service a client uses can break this alignment if it’s not configured correctly. An MSP must investigate every sending source for every client. This can be quite a time-consuming and technically demanding process. Furthermore, the SPF 10-lookup limit is a common obstacle for clients with many services. Advanced solutions like SPF flattening or macros are necessary.

The data firehose of DMARC reports is another great challenge. Each domain generates daily XML reports from receivers worldwide. Without a centralized system, MSP technicians are forced to manually collect and analyze these reports. 

This lack of centralized reporting makes it nearly impossible to get a clear view of the email security posture. This can lead to missed threats and slow response times. A single incorrect DNS entry can disrupt a client’s entire email flow.

Best Practices for MSPs Managing DMARC

MSPs need a strategic approach to overcome the many challenges of multi-domain DMARC. They should leverage:

Centralized DMARC Reporting and Monitoring

A centralized dashboard can help you aggregate and visualize DMARC reports from all your clients. This allows your team to identify threats, monitor policy enforcement, and track alignment issues. You don’t have to manually log into multiple accounts.

Using DMARC Providers with MSP Support

Look for features like a multi-tenant architecture, white-labeling capabilities, and pay-as-you-go billing. These tools are designed to scale with your business and are great for MSPs. 

Standardized DMARC Policies Across Domains

Make use of a standardized onboarding process for new clients. Start every domain with a reporting-only DMARC policy (p=none). This allows you to gather data on all sending sources without impacting email flow. This, in turn, creates a predictable and repeatable workflow for your team.

Gradual Enforcement Strategy

Never jump straight to a rejection policy. Follow a phased approach:

1. Start with p=none: Monitor reports to identify all legitimate sending services.
2. Move to p=quarantine: When you have identified and authenticated all legitimate senders, you can now move to p=quarantine. This directs unauthenticated emails to the spam folder.
3. Enforce with p=reject: When you’re sure that no legitimate emails are being quarantined, you can move to the final p=reject policy. This will outright block all unauthorized emails.

Automating SPF and DKIM Management

Use tools that can automate SPF record management. For example, PowerDMARC’s PowerSPF uses macros to dynamically flatten SPF records. This will help you stay under the 10-lookup limit, and other SPF hard limits.

Enlightening Clients About DMARC Value

Many clients may not understand DMARC. Use simple datasheets and branded reports to demonstrate the value of your MSP email security services. Show them the threats you’ve blocked and the improvements in their email deliverability.

Tools and Solutions for Multi-Domain DMARC Management

The right MSP-friendly DMARC platforms will help you manage email authentication at scale.

Here are some top MSP-friendly DMARC platforms:

PowerDMARC

PowerDMARC offers a fully white-labeled, multi-tenant platform for effortless multi-domain management. It includes features like automated SPF flattening, PSA integration, and support for 11 languages. Such strengths make PowerDMARC ideal for a global MSP business.

Highlights:

• Multi-tenant self-service multilingual control panel for MSPs
• Ability to customize the platform with your own branding, domain, and login portal.
• Built with multi-tenancy, pay-as-you-go billing, and PSA integrations.
• Full platform white labeling with custom login URL, sign up page, hosted solution and analysis tools
• Provides hosted DMARC, SPF, DKIM, BIMI, MTA-STS, and TLS-RPT in one unified platform.

dmarcian

dmarcian is a well-known player in the space. It provides detailed reporting to help organizations move toward DMARC enforcement.

Highlights:

• Founded by one of the co-authors of the DMARC specification, it offers authoritative support and resources.
• Classifies and visualizes complex email traffic sources for large organizations.
• Offers educational materials to support MSPs and their clients.

Valimail

Valimail is a trusted provider that focuses on a ‘hands-off,’ automation-first approach. It aims to simplify the path to DMARC enforcement. Valimail does so by automating sender identification and SPF/DKIM configuration.

Highlights:

• Uses an automated approach to identify sending services without requiring manual DNS updates for SPF.
• Offers guided DMARC enforcement.
• Simplifies Brand Indicators for Message Identification (BIMI) adoption and implementation for clients. 
• Integrates well into a broader zero-trust security strategy by ensuring sender identity.

Proofpoint

Proofpoint offers email authentication as part of a broader suite of email security solutions. It provides integrated threat intelligence and protection.

Highlights:

• DMARC is part of a comprehensive email security gateway and threat protection ecosystem.
• Leverages insights from Proofpoint’s vast network to identify and block threats more effectively.
• Offers enterprise-friendly, scalable solutions. 
• Offers extensive professional services and support for complex, large-scale deployments.

OnDMARC (by Red Sift)

OnDMARC is known for its automated approach to identifying and authenticating sending services. It simplifies the process of reaching DMARC enforcement with clear, actionable steps.

Highlights:

• Provides a clean dashboard with clear, guided steps to help users achieve enforcement.
• Part of the broader Red Sift digital resilience platform, so integration with other security tools is made easy.
• Offers an automated solution to manage sending services without exceeding DNS lookups.
• Provides streamlined workflows for clients looking to implement BIMI with a VMC.

Case Studies: Real Results from Real MSPs

Here are some real-life stories where MSPs have successfully leveraged DMARC. 

1. From Vulnerability to Value-Add with HispaColex

Sebastián Valero Márquez, IT Manager at HispaColex Tech Consulting, recognized that traditional measures were no longer enough. More was necessary to protect his clients from sophisticated phishing and spoofing attacks. He needed a scalable and effective email authentication solution.

Reporting and Efficiency Workflow

By onboarding PowerDMARC’s multi-tenant dashboard, HispaColex centralized client DMARC management from day one. This boosted operational efficiency and allowed their team to monitor threats without the complexity of manual analysis.

Enhanced Security and Client Satisfaction

The platform provided comprehensive DMARC, SPF, and DKIM protection. This increased client domain protection and strengthened HispaColex’s position as a security-first MSP.

2. A New Revenue Stream with White-Labeled Services

Enrique Resendez, CEO of 1-MSP, wanted to offer DMARC as a premium service but needed a solution that could be branded as his own. “PowerDMARC gave us the tools, reports, and branding flexibility we needed to truly make DMARC management our own,” says Enrique.

Workflow

1-MSP uses the white-labeled platform to offer a fully branded email authentication MSP service. They make use of custom login URLs and branded PDF reports to deliver a seamless client experience. This has not only added a new, high-margin revenue stream but has also boosted their brand’s value and positioned them as email security experts.

Summing Up

Managing DMARC for multiple domains is no longer ‘just an option’ for MSPs; it’s a necessity for client security and business growth. Multi-domain DMARC comes with many challenges, but these can be easily overcome with the right platforms and tools. 

A strategic approach to multi-domain DMARC management will improve your security offerings and boost client trust, giving you a competitive edge in a crowded market. 

Don’t wait for a client to suffer a spoofing attack. Take proactive steps to streamline your DMARC management today with PowerDMARC!

Frequently Asked Questions

Why is DMARC important for MSPs managing multiple domains?

DMARC helps MSPs prevent phishing and spoofing across client domains. It improves email deliverability and ensures compliance with industry standards and ESP sender requirements.

What are the main challenges in managing DMARC for multiple domains?

Challenges include inconsistent DNS setups, complex SPF/DKIM alignment, handling the SPF lookup limit, and processing large volumes of DMARC reports manually.

How should MSPs approach DMARC implementation?

Start with a monitoring policy (p=none) to gather data, then gradually enforce stricter policies (p=quarantine → p=reject) after verifying all legitimate senders.

Which tools are best for multi-domain DMARC management?

Tools like PowerDMARC, dmarcian, Valimail, Proofpoint, and OnDMARC help automate reporting, simplify SPF/DKIM setup, and manage multiple domains from a central dashboard.

How does multi-domain DMARC improve client security?

It blocks unauthorized emails from being delivered, protects client brands from impersonation, and reduces the risk of phishing and financial loss.

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Milena Baghdasaryan

Content Specialist at PowerDMARC

Milena is a skilled writer and content creator with 7+ years of experience in crafting engaging content on IT, cybersecurity, virtual events, and more. She has a proven track record of delivering high-quality work for international magazines and is a graduate of prestigious institutions such as New York University Abu Dhabi, UWC China, and the College of Europe.

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