{"id":12817,"date":"2025-12-13T15:42:12","date_gmt":"2025-12-13T10:12:12","guid":{"rendered":"https:\/\/www.youstable.com\/blog\/?p=12817"},"modified":"2026-09-07T11:11:27","modified_gmt":"2026-09-07T05:41:27","slug":"configure-csf-firewall-on-linux","status":"publish","type":"post","link":"https:\/\/www.youstable.com\/blog\/configure-csf-firewall-on-linux\/","title":{"rendered":"How to Configure CSF Firewall on Linux Server &#8211; (Step-by-Step Guide 2026)"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">To configure CSF (ConfigServer Security &amp; Firewall) on a Linux server, install CSF and LFD, switch off other firewalls (UFW or firewalld), edit \/etc\/csf\/csf.conf to set TESTING=0 and define allowed ports, then enable CSF with csf -e and start LFD. Finally, whitelist your IP, reload rules, and verify connectivity.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In this step-by-step guide for 2026, you\u2019ll learn exactly how to configure CSF Firewall on Linux server the right way\u2014safely, quickly, and with best practices I use in real production hosting environments. We\u2019ll cover installation, essential settings, open ports, whitelisting and blocking, GEO\/IP rules, performance tips, and troubleshooting.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"what-is-csf-firewall-and-why-use-it\"><strong>What Is CSF Firewall and Why Use It?<\/strong><\/h2>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"2848\" height=\"1600\" src=\"https:\/\/www.youstable.com\/blog\/wp-content\/uploads\/2025\/12\/What-is-CSF-Firewall-.jpg\" alt=\"What is CSF Firewall ?\" class=\"wp-image-13000\" srcset=\"https:\/\/www.youstable.com\/blog\/wp-content\/uploads\/2025\/12\/What-is-CSF-Firewall-.jpg 2848w, https:\/\/www.youstable.com\/blog\/wp-content\/uploads\/2025\/12\/What-is-CSF-Firewall--150x84.jpg 150w\" sizes=\"auto, (max-width: 2848px) 100vw, 2848px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">ConfigServer Security &amp; Firewall (CSF) is an advanced iptables\/nftables-based firewall for Linux. It ships with LFD (Login Failure Daemon), a security daemon that monitors logs for brute force attacks and automatically blocks offending IPs. CSF is popular on cPanel, DirectAdmin, and VPS\/dedicated servers because it\u2019s feature-rich, readable, and easy to automate.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Key benefits: granular port\/IP control, auto-blocking, port flood protection, connection tracking, country blocking, custom blocklists, and control via CLI or hosting panels. On modern distributions (RHEL 9\/AlmaLinux 9, Ubuntu 24.04), CSF uses iptables-nft, which translates to nftables under the hood\u2014so it remains compatible in 2026.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"prerequisites-and-compatibility\"><strong>Prerequisites and Compatibility<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Before you configure CSF on Linux, ensure the following:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Root or sudo access<\/li>\n\n\n\n<li>Supported OS: RHEL\/CentOS\/AlmaLinux\/Rocky 7\u20139, Ubuntu 20.04\/22.04\/24.04, Debian 11\/12<\/li>\n\n\n\n<li>Only one firewall framework active: disable UFW or firewalld before enabling CSF<\/li>\n\n\n\n<li>Open SSH console ready in case you need to revert quickly<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"step-by-step-install-csf-on-linux\"><strong>Step-by-Step: Install CSF on Linux<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"1-prepare-the-server\"><strong>1) Prepare the server<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code># RHEL\/AlmaLinux\/Rocky 8\/9\nsudo dnf -y update\nsudo dnf -y install wget tar perl perl-libwww-perl iptables-services\n\n# CentOS 7\nsudo yum -y update\nsudo yum -y install wget tar perl perl-libwww-perl iptables-services\n\n# Ubuntu\/Debian\nsudo apt update\nsudo apt -y install wget tar perl libwww-perl liblwp-protocol-https-perl<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"2-stop-other-firewall-managers\"><strong>2) Stop other firewall managers<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code># If firewalld is present (RHEL-based)\nsudo systemctl stop firewalld\nsudo systemctl disable firewalld\n\n# If UFW is present (Debian\/Ubuntu)\nsudo ufw disable<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"3-download-and-install-csf\"><strong>3) Download and install CSF<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>cd \/usr\/src\nsudo wget https:\/\/download.configserver.com\/csf.tgz\nsudo tar -xzf csf.tgz\ncd csf\nsudo sh install.sh\n\n# Test environment compatibility\nsudo perl \/usr\/local\/csf\/bin\/csftest.pl<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">If you use cPanel\/WHM or DirectAdmin, CSF\u2019s installer automatically adds a GUI under your panel\u2019s Plugins section. On Webmin, there\u2019s a dedicated CSF module you can enable post-install.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"baseline-configuration-must-do-settings\"><strong>Baseline Configuration (Must-Do Settings)<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"set-testing-mode-off-and-define-ports\"><strong>Set testing mode off and define ports<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">By default, CSF installs in testing mode. Edit the main configuration file and set your core rules before enabling.<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>sudo nano \/etc\/csf\/csf.conf<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Recommended minimum changes:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code># Disable testing mode (important)\nTESTING = \"0\"\n\n# SSH port (match your actual SSH port)\nTCP_IN = \"22,80,443\"\nTCP_OUT = \"80,443,53\"\n\n# Optional common services (uncomment as needed)\n# Add mail if this is a mail server:\n# TCP_IN = \"22,25,465,587,110,995,143,993,80,443\"\n# Add FTP passive range if you run FTP:\n# TCP_IN = \"21,20,30000:35000,80,443,22\"\n\n# UDP for DNS if needed\n# UDP_IN = \"53\"\n# UDP_OUT = \"53,123\"\n\n# Tighten syslog access\nRESTRICT_SYSLOG = \"3\"\n\n# Email notifications (set to a valid address to get alerts)\nLF_ALERT_TO = \"admin@example.com\"<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Adjust the port list to exactly what your applications require. Minimal exposure equals better security.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"enable-and-verify-csf-lfd\"><strong>Enable and Verify CSF\/LFD<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"1-enable-rules-and-start-lfd\"><strong>1) Enable rules and start LFD<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code># Enable CSF rules\nsudo csf -e\n\n# Start and enable LFD daemon\nsudo systemctl enable --now lfd\n\n# List active rules\nsudo csf -l<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"2-whitelist-your-ip-and-test-connectivity\"><strong>2) Whitelist your IP and test connectivity<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code># Replace with your public IP\nsudo csf -a 203.0.113.10 \"Office IP\"\nsudo csf -r   # reload rules\n\n# Verify server is reachable on SSH and web ports\nsudo ss -tulpn | egrep ':22|:80|:443'\nsudo iptables -L -n | head<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Important: Always keep an additional console (VNC\/IPMI\/serial) open when applying new firewall rules, so you can revert if you misconfigure <a href=\"https:\/\/www.youstable.com\/blog\/how-to-enable-ssh-access-for-clients-or-users\/\">SSH access.<\/a><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"everyday-csf-commands-allow-block-open-ports\"><strong>Everyday CSF Commands (Allow, Block, Open Ports)<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"allow-deny-and-temp-allow-deny-ips\"><strong>Allow, deny, and temp allow\/deny IPs<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code># Permanently allow an IP\nsudo csf -a 203.0.113.10 \"Office\"\n\n# Permanently block an IP\nsudo csf -d 198.51.100.7 \"Abusive host\"\n\n# Remove from allow\/deny\nsudo csf -ar 203.0.113.10\nsudo csf -dr 198.51.100.7\n\n# Temporarily allow (3600 seconds)\nsudo csf -ta 203.0.113.10 3600\n\n# Temporarily deny (2 hours)\nsudo csf -td 203.0.113.200 7200<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"open-or-close-ports\"><strong>Open or close ports<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Edit the TCP\/UDP port lists in \/etc\/csf\/csf.conf, then reload:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>sudo nano \/etc\/csf\/csf.conf\n# Modify TCP_IN, TCP_OUT, UDP_IN, UDP_OUT\nsudo csf -r<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"enable-syn-flood-port-flood-protection\"><strong>Enable SYN flood\/port flood protection<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code># In \/etc\/csf\/csf.conf\nSYNFLOOD = \"1\"\nSYNFLOOD_RATE = \"100\/s\"\nSYNFLOOD_BURST = \"150\"\n\n# Port flood (per-port rate limiting)\nPORTFLOOD = \"80;tcp;100;5,443;tcp;100;5\"\nsudo csf -r<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"geoip-and-blocklists-use-with-care\"><strong>GeoIP and Blocklists (Use With Care)<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Country blocking and external blocklists can reduce abusive traffic but may cause false positives. Test carefully before rolling into production.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"country-allow-deny\"><strong>Country allow\/deny<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code># In \/etc\/csf\/csf.conf\nCC_DENY = \"CN,RU\"\n# or allow only specific countries (deny the rest)\n# CC_ALLOW = \"US,CA,GB\"\n# Enable CC lookup backend and update GeoIP databases per CSF docs\nsudo csf -r<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"enable-curated-blocklists\"><strong>Enable curated blocklists<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">CSF supports third-party blocklists in \/etc\/csf\/csf.blocklists. Add reputable lists and set LF_IPSET to \u201c1\u201d for ipset acceleration where supported.<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code># Example line inside \/etc\/csf\/csf.blocklists\n# abusipdb|86400|https:\/\/raw.githubusercontent.com\/abusix\/abuse-ch\/master\/abuse-ch-ipblocklist.txt\nsudo csf -r<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"best-practice-hardening-tips-for-2026\"><strong>Best-Practice Hardening Tips for 2026<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Change SSH to a non-standard port and restrict SSH to known IPs when possible<\/li>\n\n\n\n<li>Allow only required inbound services; block all else by default<\/li>\n\n\n\n<li>Enable LFD alerts and review \/var\/log\/lfd.log regularly<\/li>\n\n\n\n<li>Use ipset (LF_IPSET=1) on busy servers to speed up large blocklists<\/li>\n\n\n\n<li>Set CT_LIMIT (connection tracking) to cap concurrent connections per IP for target ports<\/li>\n\n\n\n<li>Rotate and audit CSF allow\/deny lists monthly; remove stale entries<\/li>\n\n\n\n<li>Combine CSF with fail2ban only if you understand overlaps; don\u2019t duplicate bans from the same logs<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"troubleshooting-and-recovery\"><strong>Troubleshooting and Recovery<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"locked-out-of-ssh\"><strong>Locked out of SSH?<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">If SSH is blocked, use your provider\u2019s console (VNC\/IPMI). Whitelist your IP and reload:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>sudo csf -a &lt;your-ip&gt;\nsudo csf -r<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"flush-rules-temporarily\"><strong>Flush rules temporarily<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code># Disable CSF rules (keep LFD off if troubleshooting)\nsudo csf -x\n# Re-enable when fixed\nsudo csf -e<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"useful-logs\"><strong>Useful logs<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\/var\/log\/lfd.log \u2014 LFD decisions and triggers<\/li>\n\n\n\n<li>\/var\/log\/messages or \/var\/log\/syslog \u2014 system-wide events<\/li>\n\n\n\n<li>\/etc\/csf\/csf.deny and \/etc\/csf\/csf.allow \u2014 manual entries<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"performance-and-compatibility-notes\"><strong>Performance and Compatibility Notes<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>RHEL\/AlmaLinux\/Rocky 9 and Ubuntu 24.04 use nftables; CSF leverages iptables-nft compatibility layers and works fine<\/li>\n\n\n\n<li>On high-traffic servers, prefer ipset-based lists (LF_IPSET=1) and minimize per-IP rules<\/li>\n\n\n\n<li>Keep kernel and CSF updated to ensure conntrack and IPv6 handling are robust<\/li>\n\n\n\n<li>If you rely on Docker or Kubernetes, manage chains carefully; consider isolating CSF rules from container-managed networking<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"when-managed-hosting-helps\"><strong>When Managed Hosting Helps<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">If you don\u2019t want to babysit firewall rules and incident alerts, a <a href=\"https:\/\/www.youstable.com\/blog\/benefits-of-fully-managed-dedicated-server\/\">managed VPS or dedicated server<\/a> can save hours each month. At YouStable, our engineers deploy and tune CSF\/LFD, harden SSH, and monitor logs 24\/7\u2014so your applications stay online and secure while you focus on growth.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"faqs-configure-csf-firewall-on-linux-server\"><strong>FAQs: Configure CSF Firewall on Linux Server<\/strong><\/h2>\n\n\n\t\t<section\t\thelp class=\"sc_fs_faq sc_card    \"\n\t\t\t\t>\n\t\t\t\t<h4 id=\"is-csf-better-than-ufw-or-firewalld\">Is CSF better than UFW or firewalld?<\/h4>\t\t\t\t<div>\n\t\t\t\t\t\t<div class=\"sc_fs_faq__content\">\n\t\t\t\t\n\n<p class=\"wp-block-paragraph\">CSF isn\u2019t \u201cbetter\u201d universally, but it\u2019s more feature-rich for servers: LFD auto-bans, port flood control, blocklists, and easy per-IP management. UFW\/firewalld are simpler and built-in. For hosting stacks (cPanel\/DirectAdmin) and security automation, CSF is often preferred.<\/p>\n\n\t\t\t<\/div>\n\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section\t\thelp class=\"sc_fs_faq sc_card    \"\n\t\t\t\t>\n\t\t\t\t<h4 id=\"does-csf-work-on-rhel-9-almalinux-9-with-nftables\">Does CSF work on RHEL 9\/AlmaLinux 9 with nftables?<\/h4>\t\t\t\t<div>\n\t\t\t\t\t\t<div class=\"sc_fs_faq__content\">\n\t\t\t\t\n\n<p class=\"wp-block-paragraph\">Yes. CSF uses iptables-nft on modern distributions, which translates rules to nftables. It\u2019s fully usable in 2026. Keep your system packages up to date for best compatibility.<\/p>\n\n\t\t\t<\/div>\n\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section\t\thelp class=\"sc_fs_faq sc_card    \"\n\t\t\t\t>\n\t\t\t\t<h4 id=\"how-do-i-avoid-locking-myself-out-of-ssh\">How do I avoid locking myself out of SSH?<\/h4>\t\t\t\t<div>\n\t\t\t\t\t\t<div class=\"sc_fs_faq__content\">\n\t\t\t\t\n\n<p class=\"wp-block-paragraph\">Whitelist your IP before disabling TESTING. Keep a second console session open, confirm SSH is allowed in TCP_IN, and consider restricting SSH to your static IP. If locked out, use your provider console to csf -a your IP and csf -r.<\/p>\n\n\t\t\t<\/div>\n\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section\t\thelp class=\"sc_fs_faq sc_card    \"\n\t\t\t\t>\n\t\t\t\t<h4 id=\"how-do-i-open-ports-80-and-443-in-csf\">How do I open ports 80 and 443 in CSF?<\/h4>\t\t\t\t<div>\n\t\t\t\t\t\t<div class=\"sc_fs_faq__content\">\n\t\t\t\t\n\n<p class=\"wp-block-paragraph\">Edit \/etc\/csf\/csf.conf, add 80 and 443 to TCP_IN and ensure they exist in TCP_OUT if your app makes outbound calls. Then run sudo csf -r to reload rules. Verify with ss -tulpn and an external port scan.<\/p>\n\n\t\t\t<\/div>\n\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section\t\thelp class=\"sc_fs_faq sc_card    \"\n\t\t\t\t>\n\t\t\t\t<h4 id=\"how-do-i-uninstall-csf\">How do I uninstall CSF?<\/h4>\t\t\t\t<div>\n\t\t\t\t\t\t<div class=\"sc_fs_faq__content\">\n\t\t\t\t\n\n<p class=\"wp-block-paragraph\">Disable it, run the uninstaller, then restore your preferred firewall:<\/p>\n\n\t\t\t<\/div>\n\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section\t\thelp class=\"sc_fs_faq sc_card    \"\n\t\t\t\t>\n\t\t\t\t<h4><\/h4>\t\t\t\t<div>\n\t\t\t\t\t\t<div class=\"sc_fs_faq__content\">\n\t\t\t\t\n\n<p class=\"wp-block-paragraph\">sudo csf -x<br>cd \/usr\/src\/csf<br>sudo sh uninstall.sh<br># Re-enable firewalld or UFW if desired<br>sudo systemctl enable &#8211;now firewalld  # or: sudo ufw enable<\/p>\n\n\t\t\t<\/div>\n\t\t<\/div>\n\t\t<\/section>\n\t\t\n<script type=\"application\/ld+json\">\n\t{\n\t\t\"@context\": \"https:\/\/schema.org\",\n\t\t\"@type\": \"FAQPage\",\n\t\t\"mainEntity\": [\n\t\t\t\t\t{\n\t\t\t\t\"@type\": \"Question\",\n\t\t\t\t\"name\": \"Is CSF better than UFW or firewalld?\",\n\t\t\t\t\"acceptedAnswer\": {\n\t\t\t\t\t\"@type\": \"Answer\",\n\t\t\t\t\t\"text\": \"<p>CSF isn\u2019t \u201cbetter\u201d universally, but it\u2019s more feature-rich for servers: LFD auto-bans, port flood control, blocklists, and easy per-IP management. UFW\/firewalld are simpler and built-in. For hosting stacks (cPanel\/DirectAdmin) and security automation, CSF is often preferred.<\/p>\"\n\t\t\t\t\t\t\t\t\t}\n\t\t\t}\n\t\t\t,\t\t\t\t{\n\t\t\t\t\"@type\": \"Question\",\n\t\t\t\t\"name\": \"Does CSF work on RHEL 9\/AlmaLinux 9 with nftables?\",\n\t\t\t\t\"acceptedAnswer\": {\n\t\t\t\t\t\"@type\": \"Answer\",\n\t\t\t\t\t\"text\": \"<p>Yes. CSF uses iptables-nft on modern distributions, which translates rules to nftables. It\u2019s fully usable in 2026. Keep your system packages up to date for best compatibility.<\/p>\"\n\t\t\t\t\t\t\t\t\t}\n\t\t\t}\n\t\t\t,\t\t\t\t{\n\t\t\t\t\"@type\": \"Question\",\n\t\t\t\t\"name\": \"How do I avoid locking myself out of SSH?\",\n\t\t\t\t\"acceptedAnswer\": {\n\t\t\t\t\t\"@type\": \"Answer\",\n\t\t\t\t\t\"text\": \"<p>Whitelist your IP before disabling TESTING. Keep a second console session open, confirm SSH is allowed in TCP_IN, and consider restricting SSH to your static IP. If locked out, use your provider console to csf -a your IP and csf -r.<\/p>\"\n\t\t\t\t\t\t\t\t\t}\n\t\t\t}\n\t\t\t,\t\t\t\t{\n\t\t\t\t\"@type\": \"Question\",\n\t\t\t\t\"name\": \"How do I open ports 80 and 443 in CSF?\",\n\t\t\t\t\"acceptedAnswer\": {\n\t\t\t\t\t\"@type\": \"Answer\",\n\t\t\t\t\t\"text\": \"<p>Edit \/etc\/csf\/csf.conf, add 80 and 443 to TCP_IN and ensure they exist in TCP_OUT if your app makes outbound calls. Then run sudo csf -r to reload rules. Verify with ss -tulpn and an external port scan.<\/p>\"\n\t\t\t\t\t\t\t\t\t}\n\t\t\t}\n\t\t\t,\t\t\t\t{\n\t\t\t\t\"@type\": \"Question\",\n\t\t\t\t\"name\": \"How do I uninstall CSF?\",\n\t\t\t\t\"acceptedAnswer\": {\n\t\t\t\t\t\"@type\": \"Answer\",\n\t\t\t\t\t\"text\": \"<p>Disable it, run the uninstaller, then restore your preferred firewall:<\/p>\"\n\t\t\t\t\t\t\t\t\t}\n\t\t\t}\n\t\t\t,\t\t\t\t{\n\t\t\t\t\"@type\": \"Question\",\n\t\t\t\t\"name\": \"\",\n\t\t\t\t\"acceptedAnswer\": {\n\t\t\t\t\t\"@type\": \"Answer\",\n\t\t\t\t\t\"text\": \"<p>sudo csf -x<br>cd \/usr\/src\/csf<br>sudo sh uninstall.sh<br># Re-enable firewalld or UFW if desired<br>sudo systemctl enable --now firewalld  # or: sudo ufw enable<\/p>\"\n\t\t\t\t\t\t\t\t\t}\n\t\t\t}\n\t\t\t\t\t\t]\n\t}\n<\/script>\n\n\n\n<h2 class=\"wp-block-heading\" class=\"wp-block-heading\" id=\"final-thoughts\"><strong>Final Thoughts<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Configuring CSF on a Linux server is straightforward and powerful when done methodically. Install CSF\/LFD, define only the ports you need, enable flood protection, and maintain allow\/deny lists. With smart defaults and regular reviews, CSF gives you enterprise-grade control without the complexity.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Need a secure starting point? YouStable can provision your VPS or dedicated server with a hardened CSF profile, proactive LFD alerts, and 24\/7 support\u2014so your stack stays fast, locked down, and easy to manage.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>To configure CSF (ConfigServer Security &amp; Firewall) on a Linux server, install CSF and LFD, switch off other firewalls (UFW [&hellip;]<\/p>\n","protected":false},"author":13,"featured_media":12984,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"iawp_total_views":110,"footnotes":""},"categories":[350,2262],"tags":[],"class_list":["post-12817","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-knowledgebase","category-kb-security"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.youstable.com\/blog\/wp-json\/wp\/v2\/posts\/12817","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.youstable.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.youstable.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.youstable.com\/blog\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/www.youstable.com\/blog\/wp-json\/wp\/v2\/comments?post=12817"}],"version-history":[{"count":1,"href":"https:\/\/www.youstable.com\/blog\/wp-json\/wp\/v2\/posts\/12817\/revisions"}],"predecessor-version":[{"id":23226,"href":"https:\/\/www.youstable.com\/blog\/wp-json\/wp\/v2\/posts\/12817\/revisions\/23226"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.youstable.com\/blog\/wp-json\/wp\/v2\/media\/12984"}],"wp:attachment":[{"href":"https:\/\/www.youstable.com\/blog\/wp-json\/wp\/v2\/media?parent=12817"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.youstable.com\/blog\/wp-json\/wp\/v2\/categories?post=12817"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.youstable.com\/blog\/wp-json\/wp\/v2\/tags?post=12817"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}