Security

Learn how to check and interpret the kernel entropy pool on Linux, why low entropy can slow down SSL handshakes and SSH sessions, and what to do when the pool runs dry.

A quick reference for verifying AES-NI hardware acceleration across Java, OpenSSL, and the CPU itself. Includes benchmark commands to confirm the instruction set is actually being used.

A quick two-step check to confirm the Kerberos key version number in your KDC database matches the value stored in a local keytab file. Mismatched KVNO values are a common cause of authentication failures in Hadoop and other Kerberized services.

Kerberos authentication failures can be tricky to diagnose without detailed logging. This guide walks you through enabling Kerberos event logging on a Windows machine via the registry so you can capture authentication events in the system log.

Specific JDK 1.8.0 builds (u40, u45, u91, u92) are known to break SPNEGO authentication and Hadoop web interfaces. This post documents the affected versions, the symptoms, and the recommended downgrade path.

Kerberos cross-realm authentication relies entirely on TGS exchanges between KDCs. Understanding the three-step ticket flow makes it easier to troubleshoot trust relationships between domains.