Microsoft 365

Using MXGuard as an external gateway in front of Microsoft 365 / Exchange Online.

Microsoft 365 has built-in protection via Defender for Office 365. MXGuard runs as an extra filtering layer before mail reaches Microsoft — so you get the best of both systems.

Step 1. Find your domain's MX address in M365

Check your domain's DNS records and note the current MX record, something like company-com.mail.protection.outlook.com — this will become the target server for MXGuard.

Step 2. Add the domain to MXGuard

In the MXGuard panel → Domains → Add: enter company-com.mail.protection.outlook.com in the "Target server" field.

Step 3. Change your MX records

Point your domain's MX records to MXGuard's servers. Mail now passes through our filter first, then gets delivered to Microsoft 365.

Step 4. Configure Enhanced Filtering

In the Microsoft 365 Security Center → Email & collaboration → Policies → Enhanced Filtering for Connectors. Enter MXGuard's IPs so Microsoft sees the real sender IP instead of ours.

Step 5. Update your SPF record

Add this to your domain's SPF record:

v=spf1 include:spf.mxguard.net include:spf.protection.outlook.com ~all