{"id":3510,"date":"2024-05-30T20:41:37","date_gmt":"2024-05-30T15:11:37","guid":{"rendered":"https:\/\/www.veeble.org\/kb\/?p=3510"},"modified":"2025-04-09T12:34:47","modified_gmt":"2025-04-09T07:04:47","slug":"how-to-close-a-specific-port-on-linux","status":"publish","type":"post","link":"https:\/\/www.veeble.com\/kb\/how-to-close-a-specific-port-on-linux\/","title":{"rendered":"How to Close a Specific Port on Linux"},"content":{"rendered":"\n
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\"How<\/a><\/figure>\n<\/figure>\n\n\n\n

On a Linux system, closing a particular port might help increase security or free up system resources. This short tutorial will walk you through closing a port using IPtables<\/a>, FirewallD<\/a>, UFW<\/a>, or stopping the service. If you are looking for a tutorial to open a port in Linux, please check our tutorial: How to Open a Specific Port on Linux<\/a><\/p>\n\n\n\t\t\t\t

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\n\t\t\t\t\t\t\tTable Of Contents\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t
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  1. How to Check Open Ports on Linux<\/a>
  2. How to Close a Port Using UFW (Uncomplicated Firewall)<\/a>
  3. How to Close a Port Using iptables<\/a>
  4. How to Close a Port Using Firewalld<\/a>
  5. How to Stop a Service to Close a Port<\/a>
  6. Ignite Your Online Performance<\/a><\/ol>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\n\n\n

    <\/p>\n\n\n\n

    <\/p>\n\n\n

    How to Check Open Ports on Linux<\/h3>\n\n\n

    First, let’s see which ports are open. You can use one of these commands:<\/p>\n\n\n

    Using netstat:<\/h6>\n\n\n
    sudo netstat -tuln<\/code><\/pre>\n\n\n\n
    Below is a sample output in which underlined in red are the ports which are opened. (22 and 53)<\/p>\n\n\n\n
    \n
    \"sample<\/a><\/figure>\n<\/figure>\n\n\n\n
    <\/p>\n\n\n
    Using ss:<\/h6>\n\n\n
    sudo ss -tuln<\/code><\/pre>\n\n\n\n
    Below is a sample output in which underlined in red are the ports which are opened. (22 and 53)<\/p>\n\n\n\n
    \n
    \"sample<\/a><\/figure>\n<\/figure>\n\n\n\n
    <\/p>\n\n\n
    Using lsof:<\/h6>\n\n\n
    The lsof<\/code> command is mostly not preinstalled on Linux systems. You need to manually install this command to use. If you are using a Debian-based system like Ubuntu, use the command: sudo apt-get install lsof<\/code> to install. For Centos\/Redhat: sudo yum install lsof<\/code> and for Fedora: sudo dnf install lsof<\/code><\/pre>\n\n\n\n
    sudo lsof -i -P -n<\/code><\/pre>\n\n\n\n
    Below is a sample output in which underlined in red are the ports which are opened. (22 and 53)<\/p>\n\n\n\n
    \n
    \"sample<\/a><\/figure>\n<\/figure>\n\n\n\n
    These commands will list all the open ports on your system.<\/p>\n\n\n\n
    <\/p>\n\n\n
    How to Close a Port Using UFW (Uncomplicated Firewall)<\/h3>\n\n\n
    For Ubuntu and other Debian-based systems, UFW<\/strong> is a straightforward firewall management application.<\/p>\n\n\n
    Install UFW (if it’s not installed):<\/h6>\n\n\n
    sudo apt-get install ufw\nsudo ufw enable<\/code><\/pre>\n\n\n
    Close the Port:<\/h6>\n\n\n
    Replace <port_number><\/code> with the port number, you want to close.<\/p>\n\n\n\n
    sudo ufw deny <port_number><\/code><\/pre>\n\n\n\n
    Example screenshot:<\/p>\n\n\n\n
    \n
    \"close<\/a><\/figure>\n<\/figure>\n\n\n
    Check UFW Status:<\/h6>\n\n\n
    sudo ufw status<\/code><\/pre>\n\n\n\n
    <\/p>\n\n\n
    How to Close a Port Using iptables<\/h3>\n\n\n
    A more sophisticated tool for controlling firewall rules is IPtables. To install IPtables use the command: sudo apt-get install iptables<\/code> if it was not installed.<\/p>\n\n\n
    Block the Port:<\/h6>\n\n\n
    Replace <port_number><\/code> with the port number, you want to close.<\/p>\n\n\n\n
    sudo iptables -A INPUT -p tcp --dport <port_number> -j DROP\nsudo iptables -A INPUT -p udp --dport <port_number> -j DROP<\/code><\/pre>\n\n\n\n
    Example screenshot:<\/p>\n\n\n\n
    \n
    \"Block<\/a><\/figure>\n<\/figure>\n\n\n\n
    <\/p>\n\n\n
    Save IPtables Rules:<\/h6>\n\n\n
    On Debian-based systems:<\/p>\n\n\n\n
    sudo sh -c \"iptables-save > \/etc\/iptables\/rules.v4\"<\/code><\/pre>\n\n\n
    On Red Hat-based systems:<\/h6>\n\n\n
    sudo service iptables save<\/code><\/pre>\n\n\n\n
    <\/p>\n\n\n
    How to Close a Port Using Firewalld<\/h3>\n\n\n
    Firewalld<\/strong> is the default firewall tool for CentOS and Fedora.<\/p>\n\n\n
    Install Firewalld (if it’s not installed):<\/h6>\n\n\n
    sudo yum install firewalld<\/code><\/pre>\n\n\n
    Block the Port:<\/h6>\n\n\n
    Replace <port_number><\/code> with the port number, you want to close.<\/p>\n\n\n\n
    sudo firewall-cmd --permanent --remove-port=<port_number>\/tcp\nsudo firewall-cmd --permanent --remove-port=<port_number>\/udp<\/code><\/pre>\n\n\n\n
    Example screenshot:<\/p>\n\n\n\n
    \n
    \"Block<\/a><\/figure>\n<\/figure>\n\n\n\n
    <\/p>\n\n\n
    Reload Firewalld:<\/h6>\n\n\n
    sudo firewall-cmd --reload<\/code><\/pre>\n\n\n
    Check Firewalld Status:<\/h6>\n\n\n
    sudo firewall-cmd --list-all<\/code><\/pre>\n\n\n\n
    <\/p>\n\n\n
    How to Stop a Service to Close a Port<\/h3>\n\n\n
    Sometimes, a port is open because a service is using it. Stopping the service will close the port. In that case, blocking the service will be the best option rather than closing the port.<\/p>\n\n\n
    Identify the Service:<\/h6>\n\n\n
    Use netstat<\/code>, ss<\/code>, or lsof<\/code> to find which service is using the port.<\/p>\n\n\n\n
    sudo netstat -tuln | grep <port_number><\/code><\/pre>\n\n\n\n
    OR<\/p>\n\n\n\n
    sudo ss -tuln | grep <port_number><\/code><\/pre>\n\n\n\n
    OR<\/p>\n\n\n\n
    sudo lsof -i :<port_number><\/code><\/pre>\n\n\n\n
    For Example:<\/p>\n\n\n\n
    \n
    \"checking<\/a><\/figure>\n<\/figure>\n\n\n\n
    Replace <port_number><\/code> with the actual port number.<\/p>\n\n\n
    Stop the Service:<\/h6>\n\n\n
    Replace <service_name><\/code> with the name of the service.<\/p>\n\n\n\n
    sudo systemctl stop <service_name><\/code><\/pre>\n\n\n\n
    For example:<\/p>\n\n\n\n
    \n
    \"Stopping<\/a><\/figure>\n<\/figure>\n\n\n\n
    <\/p>\n\n\n
    Disable the Service (if needed):<\/h6>\n\n\n
    This prevents the service from starting at boot.<\/p>\n\n\n\n
    sudo systemctl disable <service_name><\/code><\/pre>\n\n\n\n
    <\/p>\n\n\n\n
    On Linux, there are multiple methods to close a port: UFW, IPtables, Firewalld, or terminating a service. Select the approach that best suits your needs. For simplicity, UFW is a great choice. For more control, IPtables is ideal. Firewalld is perfect for Red Hat-based distributions, and stopping a service directly is effective when dealing with a specific application. Always ensure you correctly identify the service using the port before stopping it. <\/p>\n\n\n\n
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    Related Blogs:<\/strong><\/p>\n\n\n\n
    \n
    How to Open a Specific Port on Linux<\/a><\/blockquote>