SysAdmin

Learn how to insert iptables rules at a specific position using the -I flag, with syntax breakdown and a practical SSH example.

Configure the soft and hard stack limits for the Apache user in /etc/security/limits.conf to prevent segmentation faults caused by insufficient stack space.

A quick awk pipeline to pull wp-login.php access attempts from web server logs and flag IPs that exceed a threshold. Useful for spotting brute-force or scanning activity against WordPress sites.

A quick one-liner to inspect the stack size limit applied to a running Apache httpd process on Linux. Useful when debugging segfaults or tuning worker memory.

A quick reference for running mysqlcheck to verify and optimize MySQL databases, including the -A flag to target every database on the server in one pass.

A quick way to verify whether a specific IP address is blocked by iptables rules on a Linux host. Covers the exact command and how to read the output.