Linux Firewall Basics: ufw vs firewalld (Quick Start)

<p><img alt="Linux ufw firewall status showing allowed SSH and web ports" src="https://blog.gnomeitsolutions.com/wp-content/uploads/2026/08/blogger-firewall-ufw.png" style="max-width:100%;height:auto;border-radius:6px;"/></p><p>Every Linux server needs a firewall. On Debian/Ubuntu you usually see <strong>ufw</strong>; on RHEL/CentOS/Rocky it's <strong>firewalld</strong>. Both wrap iptables/nftables—pick one and stay consistent.</p><h2>ufw (Ubuntu / Debian)</h2><pre><code>sudo ufw default deny incoming sudo ufw default allow outgoing sudo ufw allow 22/tcp comment 'SSH' sudo ufw allow 80,443/tcp comment 'Web' sudo ufw enable sudo ufw status numbered</code></pre><h2>firewalld (RHEL family)</h2><pre><code>sudo systemctl enable --now firewalld sudo firewall-cmd --permanent --add-service=ssh sudo firewall-cmd --permanent --add-service=http sudo firewall-cmd --permanent --add-service=https sudo firewall-cmd --reload sudo firewall-cmd --list-all</code></pre><h2>Before you lock yourself out</h2><ul><li>Keep an active SSH session open while testing rules</li><li>Allow SSH <em>before</em> enabling the firewall</li><li>Use a cloud console (VNC/serial) as backup access</li></ul>

Linux Firewall Basics: ufw vs firewalld (Quick Start)

Every Linux server needs a firewall. On Debian/Ubuntu you usually see ufw ; on RHEL/CentOS/Rocky it's firewalld . Both wrap iptables/nft...

Read more »