Security

A quick guide to diagnosing and resolving the ‘Key has been revoked’ error in the Linux kernel keyring using keyctl commands.

How to verify and manage HTTP service principal names in Active Directory using ldapsearch and setspn, including a note about Centrify’s uppercase requirement.

A practical cheat sheet of openssl s_client commands for inspecting, verifying, and troubleshooting SSL certificates in production environments.

A practical look at why the MIT krb5 KDC rejects a TGS-REQ with KRB_AP_ERR_NOT_US, including the exact validation logic and the most common root causes behind the error.