In this Microsoft 365 Email Security article, we will explain how to prevent Microsoft 365 emails from blacklisting.
As an IT consultancy in the Microsoft 365 space, we help Microsoft 365 customers that get affected by anti-spam systems that blacklist and graylist their email domains as spam.
Once a domain is marked as a spam sender, the recipient’s email servers will reject any email coming from the domain. In the best-case scenario, their email will be quarantined for days until released by the recipient’s IT department.
Both scenarios are devastating to business and, in most cases, can be prevented and resolved with the right email security strategy. In this article, we will explain some of the tools and services you can use to prevent your domain from being blacklisted or whitelisted your domain.
How to Prevent Microsoft 365 Emails from Blacklisting
Although email security and delivery success is a wide topic, over the years, we have seen a few tools that can increase the delivery rate of email to customers and also prevent email domains from being blacklisted.
DKIM (DomainKeys Identified Mail)
Enabling DKIM on your Microsoft 365 can increase the chances of being blacklisted. DKIM helps recipient mail servers to validate the sender’s mail servers and authenticate a domain.
If your business uses several email domains, enable DKIM for each domain. Many organisations make the common mistake of enabling DKIM on a single domain.
SPF (Sender Policy Framework)
One of the most important tools and policies for ensuring your domain does not get blacklisted is to use SPF. SPF allows us to add third-party email delivery tools like ServiceNow that use our domain to send emails.
A common cause for blacklisting is that many organisations use third-party tools that relay and send emails on their behalf without adding SPF records of the service into their SPF. Doing that will almost guarantee your domain will get blacklisted and rejected.
DMARC (Domain-based Message Authentication, Reporting, and Conformance)
DMARC uses DKIM and SPF to build a policy that tells receiving servers what to do if an email fails authentication checks. It also provides a way for domain owners to receive reports on authentication failures.
Without DMARC reporting, it is almost impossible to troubleshoot what a domain is being blacklisted.
Microsoft 365 Quarantine
As we explained in our previous article, Microsoft 365’s quarantine feature helps manage suspicious emails by isolating them before they reach the inbox.
his feature allows administrators to review, release, or delete these emails based on their legitimacy.
Recap
Preventing an email domain from being blacklisted is a task that needs to be a top priority for any business that uses its email to operate and conduct business.
At CPI, we assist many organizations in whitelisting their email domains. The process may take some time and require multiple steps; therefore, we recommend that you enhance your email security while your domain is in good standing.