A fresh Linux server ships with no firewall rules at all. Every listener you start is instantly reachable from the whole internet. The fix is a short, well-understood baseline: default-deny inbound, allow established traffic, and an explicit allow-list for the services you actually run. This guide builds that baseline in nftables rule by rule, explains the parts everyone gets wrong (ICMP and IPv6), shows the same policy in ufw and firewalld, and covers how not to lock yourself out, plus the Docker port-publishing trap.

If your server runs a current Debian, Ubuntu, or RHEL-family distro, your "iptables" rules are almost certainly already executing inside nftables. The iptables command has been a compatibility shim since 2019. The real question isn't which one wins; it's whether to keep writing rules in a legacy syntax on top of the new engine. This guide covers what actually changed architecturally, a side-by-side syntax comparison, what the honest performance data says, and a migration path that won't break Docker or lock you out.

A Linux dedicated server gives you a whole physical machine with no hypervisor in the way, but which distribution should you run on it? Ubuntu, Debian, the CentOS successors, and RHEL each make different trade-offs around release cadence, support, and cost. This guide explains what a bare-metal Linux server actually is, when it beats a VPS or cloud instance, and how to pick a distribution by workload and support needs, with a side-by-side comparison and links to the right server for each.

A freshly provisioned server starts receiving SSH probes within minutes of its IP going live; honeypot studies show most exposed machines are attacked within a day. The good news: the defences that matter are a short, boring, one-hour checklist, not a security research project. This guide walks the eight steps in order (users and SSH keys, firewall baseline, automatic updates, fail2ban, time sync, a listener audit, and logging) with the exact commands for Debian/Ubuntu and the RHEL family, plus an honest list of what not to waste your first hour on.