PostgreSQL (also called Postgres) is a free, open-source, object-relational database management system with a strong reputation for reliability, SQL standards compliance, and advanced feature support. It handles complex queries, JSON data, full-text search, and custom data types, making it a natural...

VMware Workstation Player is a mature, stable virtualization platform that lets you run multiple isolated operating systems on a single physical machine. You can create your own virtual machines or run virtual appliances from VMware’s Solution Exchange. Common uses include testing...

A properly configured firewall is one of the most important layers of security for any internet-facing server. UFW (Uncomplicated Firewall) is a user-friendly front-end for managing iptables rules that ships pre-installed on Ubuntu. Its defaults are sensible: block all incoming connections, allow all outgoing connections. No outside traffic reaches your server unless you explicitly open a port. This guide covers how to configure a UFW firewall on Ubuntu 18.04, from setting default policies and application profiles to writing allow and deny rules for specific ports, IPs, and subnets. Configure UFW Firewall on Ubuntu: Defaults, SSH, and Application Profiles If UFW is not installed, add it with: Check the current status: Application profiles. When you install a service with apt, it registers a profile in /etc/ufw/applications.d/. List all available profiles: Use a profile name or a port number interchangeably when writing rules. To see what ports a profile covers: Allow SSH before enabling UFW. This is the most critical step. If you enable UFW without an SSH rule and you are on a remote server, you lose access immediately: If your SSH daemon runs on a non-standard port, use the port number instead, for example sudo ufw allow 4422/tcp. Enable UFW: Type y at the prompt to confirm. Allow Port Ranges, Specific IPs, Subnets, and Network Interface Rules Common...

UFW (Uncomplicated Firewall) is a user-friendly front-end for managing iptables rules on Ubuntu. It ships pre-installed and simplifies tasks that would otherwise require writing complex iptables commands by hand. UFW is the standard way to control inbound and outbound traffic on...