DMARC Creator for Agencies and MSPs — Manage Client Email Authentication

If you manage email or DNS for client domains, DMARC should be on every single one. Whether you run a marketing agency, an IT managed services practice, or a consulting firm, your clients are exposed without it. Not sure if a client actually needs it? Our article on whether you need DMARC covers the scenarios where it is essential. The challenge is not setting up one DMARC record. It is setting up dozens or hundreds of them, keeping them monitored, and making sure nothing drifts out of compliance.

This guide covers the practical workflow for agencies and MSPs deploying DMARC across a client portfolio, including how to handle the unique challenges that come with managing domains you do not own.

The Multi-Client Challenge

A single business sets up DMARC once and moves on. An agency or MSP does it repeatedly, across clients with wildly different setups. Some clients use Google Workspace, others use Microsoft 365, and some have legacy on-premise servers. Each client has a different mix of marketing tools, support desks, and transactional email services. DNS is hosted in different places. Some clients have existing records that are incomplete or broken.

The common problems agencies face:

• No two clients have the same sending stack. You cannot use a single template and apply it everywhere. Each domain needs its SPF, DKIM, and DMARC records tailored to its actual senders. Understanding how SPF, DKIM, and DMARC work together is essential for getting this right across diverse client setups.
• DNS access varies. Some clients give you full DNS control. Others require you to submit changes through a ticket system or their internal IT team. Some have DNS locked behind a registrar account with credentials nobody remembers.
• Existing records are often wrong. Many domains have partial SPF records, no DKIM, or a DMARC record that was set up years ago and never updated. You need to audit before you build.
• Clients add services without telling you. A client signs up for a new marketing tool and starts sending email from their domain without updating SPF or DKIM. The first sign of trouble is their email landing in spam.

Why Agencies Should Own DMARC for Every Client

Setting up DMARC for your clients is not just a nice add-on. It directly affects the work you are already doing. If you manage a client's email marketing and their domain gets spoofed, your campaigns suffer from the reputation damage. If you manage their IT infrastructure and their email authentication breaks, the support tickets land on your desk.

The Agency DMARC Workflow

Here is a repeatable process for deploying DMARC across client domains. This works whether you have ten clients or two hundred.

Handling Non-Sending and Parked Domains

Many of your clients own domains they do not use for email. These might be alternate TLDs, old brand names, typo domains purchased defensively, or domains reserved for future projects. Every one of these needs a DMARC record. For clients with complex domain structures, our guide on DMARC for subdomains covers how to apply policies across parent and child domains.

For any domain that does not send email, publish this immediately:

v=DMARC1; p=reject; sp=reject;

Pair it with v=spf1 -all for SPF and no DKIM records. This tells every receiving server in the world that no email from this domain is legitimate. There is no monitoring period needed because there is no legitimate mail to protect.

This is low-effort, high-impact work. A single afternoon spent locking down parked domains across your client portfolio eliminates a significant spoofing surface.

Monitoring at Scale

Setting up DMARC records is a project. Keeping them working is an ongoing service. For a single domain, you might manually check records once a month. For a portfolio of client domains, manual checking does not scale.

Things that break DMARC over time:

• A client's IT team updates DNS and accidentally deletes or modifies the DMARC record
• A new sending service is added without updating SPF or configuring DKIM
• An SPF record exceeds the ten lookup limit after adding a new include
• A DKIM key expires or a signing configuration changes during a platform migration
• A client moves their domain to a new registrar and does not transfer all DNS records

You need automated monitoring that checks every client domain daily and alerts you when something changes. This is not optional at scale — it is the difference between catching a problem in hours versus discovering it weeks later when a client calls about their email landing in spam.

Building DMARC Into Your Service Offering

For marketing agencies, DMARC fits naturally into email deliverability services. You are already managing campaigns that depend on inbox placement. Adding authentication management to your scope protects the work you are doing and gives you a new line item.

For IT MSPs, DMARC belongs in your standard security stack alongside firewalls, endpoint protection, and backup. Email is the primary attack vector for phishing, and DMARC is the primary defense against domain spoofing. It should be part of every client onboarding.

For consultants, DMARC audits are a strong entry point for new engagements. Run a quick check on a prospect's domain, show them what you find, and propose a remediation project. Most businesses have never checked their DMARC status, and the results are often eye-opening. Our DMARC best practices article is a useful reference to share with clients during onboarding.

The Email Deliverability Suite supports unlimited domains, bulk CSV import, and custom check schedules, which makes it practical for agencies managing large portfolios. You can import your entire client list, set up daily monitoring, and get alerts the moment any record changes or breaks.

Monitor Your DMARC Record

You've created your DMARC record — now make sure it keeps working. The Email Deliverability Suite watches your SPF, DKIM, DMARC, and MX records daily and alerts you when something breaks.