Diagnosing Port Conflicts in Linux: Beyond Netstat and SS

A common troubleshooting scenario involves applications, such as Tomcat running in a Docker container, failing to be accessible despite the host port appearing to be bound. This often leads to confusion, especially when one port mapping works while another fails for the same service. Problem Scenario Consider the following Docker commands: doc ...

Posted on Wed, 12 Aug 2026 16:13:24 +0000 by mazzzzz

Linux Daily Operations: Firewall, Port Management, and Process Queries

Firewall Management Check firewall status: systemctl status firewalld Start firewall: systemctl start firewalld List all firewall rules and open ports: firewall-cmd --list-all Open a specific port (e.g., 8080/tcp): firewall-cmd --add-port=8080/tcp --permanent Reload firewall to apply changes: firewall-cmd --reload Verify if a port is open: ...

Posted on Thu, 28 May 2026 16:42:32 +0000 by HuggieBear

Changing MySQL Port Number on CentOS 7

Changing MySQL Port Number on CentOS 7 When deploying MySQL on a CentOS 7 system, sometimes you need to change the default port number. This article explains how to change the port number of a MySQL database on CentOS 7. Steps 1. Connect to the MySQL Database First, connect to MySQL using the command: mysql -u root -p Enter your password to ac ...

Posted on Tue, 12 May 2026 22:48:34 +0000 by watts