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M365 Tenant Detection
Detect if your domain is running Microsoft 365. Checks MX records, autodiscover CNAME, Microsoft domain verification TXT records, and the public OpenID configuration endpoint.
Checking Microsoft 365 signals…
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What does this check?
This tool checks five independent signals to determine if a domain uses Microsoft 365: MX records pointing to Exchange Online, autodiscover CNAME entries, Microsoft domain verification TXT records (MS=xxx), Microsoft's public OpenID configuration endpoint, and Lyncdiscover records for Teams/Skype integration.
Once you confirm M365 is in use, the next step is to check whether legacy authentication is still enabled — a common configuration gap that allows attackers to bypass MFA entirely.