If your business emails have suddenly started bouncing back, landing in spam folders, or getting flagged as suspicious by recipients using Microsoft 365 or Outlook.com, you are not alone. This week Microsoft rolled out stricter enforcement of DMARC rules for senders, and it has caught a lot of businesses off guard. For something most people have never heard of, DMARC has a real impact on whether your invoices, quotes and customer communications actually get read.
What is DMARC and why does it matter
DMARC stands for Domain-based Message Authentication, Reporting and Conformance. In plain terms, it is a DNS record that tells email providers like Microsoft and Google how to treat messages that claim to come from your domain. It works alongside two other records, SPF and DKIM, to prove that an email genuinely came from you and was not sent by someone pretending to be you.
Without a correctly configured DMARC record, there is nothing stopping a scammer from sending an email that looks like it is from yourcompany.co.uk. That is exactly the kind of thing fraudsters rely on for invoice scams and phishing attacks. Email providers know this, which is why they are increasingly refusing to deliver mail from domains that do not have DMARC properly set up.
What changed this week
Microsoft has tightened how strictly it checks and enforces DMARC policies for domains sending mail into Outlook.com and Microsoft 365 inboxes. Domains with missing, misconfigured or weak DMARC records are now far more likely to have their emails rejected or sent straight to junk. This is part of a wider industry trend, Google made similar changes in 2024, and it is only going to get stricter from here.
The problem is that DMARC sits in your DNS settings, which is often managed by whoever set up your website or email years ago and then forgotten about. Many business owners do not even know who controls their DNS, let alone whether it has the right records in place.
What you need to do
What happens next depends entirely on who manages your DNS.
- If you are a Valetech customer and we manage your DNS: there is nothing you need to do. We have already reviewed and updated your DMARC settings in line with Microsoft's new requirements, so your email should continue to deliver as normal.
- If you are a Valetech customer but we do not manage your DNS: please contact your DNS provider as soon as possible to have your DMARC record checked and updated. If you are not sure who that is or how to approach it, get in touch with us and we will help you work it out.
- If you are not currently a Valetech customer: we would still recommend checking your DMARC setup this week. Get in touch and we can review your domain's email authentication for free and tell you exactly where you stand.
How to check your own setup
If you want a quick sanity check in the meantime, there are free online DMARC lookup tools that will tell you whether a record exists for your domain and roughly how strict it is. A missing record, or one set to "none" with no monitoring, is a sign it needs attention. A properly configured record should be set to "quarantine" or "reject" once you are confident all your legitimate mail sources are accounted for.
Why this is worth sorting properly
It is tempting to see DMARC as a technical box-ticking exercise, but the business impact is immediate and tangible. Emails that fail delivery mean missed quotes, delayed payments and customers who assume you are ignoring them. Left unfixed, it also leaves your domain more exposed to being impersonated in phishing attacks aimed at your own customers and suppliers.
This is exactly the kind of behind-the-scenes work that good managed IT support should be catching before it becomes a problem, rather than after. Valetech Solutions manages DNS and email security for businesses across Greater Manchester, and we monitor changes like this one as part of that service, so our customers do not have to think about it. If you want to know where your business stands, or you would simply rather this sort of thing was handled for you going forward, get in touch with Valetech Solutions.