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Configuring Microsoft Entra TLS for Secure and Reliable Authentication

Andrios Robert

• 1 min read

Microsoft Entra uses TLS to protect every connection between clients, APIs, and identity endpoints. A wrong setting can break authentication flows, fail API calls, or expose your traffic to downgrade attacks. To configure it correctly, you need to know the supported protocols, cipher suites, and certificate requirements.

Check your TLS protocol versions. Microsoft Entra requires TLS 1.2 or later. TLS 1.0 and 1.1 are deprecated and will fail. Ensure both your application and any reverse proxies enforce TLS 1.2+ by disabling legacy protocols in the OS and web server settings.

Set strong cipher suites. Weak ciphers like RC4, DES, or 3DES are blocked. Use suites with AES-GCM and SHA-256 or stronger. Prioritize ECDHE for forward secrecy. In Windows Server, manage suites via Group Policy. In Nginx or Apache, define them directly in the config file. Match your config against Microsoft’s published cipher list for Entra endpoints.

Validate your certificates. Certificates must be signed by a trusted certificate authority. Use SHA-256 or stronger for the signature algorithm. Ensure the certificate chain is complete and the SAN (Subject Alternative Name) matches the exact hostnames used by your Entra apps. Renew certificates before expiration to avoid downtime.

Test every endpoint. Use tools like OpenSSL, PowerShell’s Test-TlsConnection, or external scanners to verify that your application negotiates the right protocol and cipher suite with Entra. Test from multiple regions to catch edge-case failures in CDN or load balancer layers.

A proper Microsoft Entra TLS configuration doesn’t just meet compliance—it ensures stable, secure authentication at scale. Missteps here surface as intermittent sign-in failures, which are harder to debug than outright outages.

Set it up right, test with discipline, and track changes. Then deploy your authentication flow to production with confidence.

Want to see it working in minutes? Build and test your secure Microsoft Entra integration on hoop.dev now.