How To Check Firewall Status In Centos 7

When it comes to securing your system and protecting it from unauthorized access, checking the firewall status is an essential step. In CentOS 7, knowing the status of your firewall can help ensure that your network is adequately protected. So, let's explore how you can easily check the firewall status in CentOS 7.

In CentOS 7, you can use the 'firewall-cmd' command-line tool to check the firewall status. This tool provides a simple and effective way to manage firewall rules and configurations. By running the command 'firewall-cmd --state', you can quickly determine the current status of the firewall. This information will enable you to take necessary actions to strengthen your system's security and address any potential vulnerabilities.

Introduction: Understanding Firewall in CentOS 7

In a CentOS 7 system, the firewall plays a crucial role in ensuring network security by monitoring and controlling incoming and outgoing traffic. It acts as a barrier or protective shield that filters network packets to allow or deny access based on predefined rules. It is essential to regularly check the firewall status to ensure that the system is adequately protected and that the firewall is functioning as intended. This article will guide you through various methods to check the firewall status in CentOS 7, empowering you to verify its effectiveness and make any necessary adjustments.

Using the systemctl Command

One of the easiest ways to check the firewall status in CentOS 7 is by using the systemctl command. This command allows you to manage system services and provides a quick way to determine if the firewall is running or not. Follow the steps below:

• Open a terminal or SSH session to the CentOS 7 system.
• Type the following command to check the firewall status:

sudo systemctl status firewalld

If the firewall is running, you will see an output similar to the following:

● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2022-01-10 09:12:06 UTC; 10s ago
     Docs: man:firewalld(1)
 Main PID: 275 (firewalld)
   CGroup: /system.slice/firewalld.service
           └─275 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid

Jan 10 09:12:06 centos7 systemd[1]: Started firewalld - dynamic firewall daemon.

If the firewall is not running, the output will indicate that it is inactive or failed. In such cases, you may need to start or restart the firewall as needed using the appropriate systemctl commands.

Starting the Firewall

If the firewall is not running, you can start it using the following command:

sudo systemctl start firewalld

You can then check the firewall status again using the previous command to ensure that the firewall is now running.

Restarting the Firewall

If the firewall is already running, but you need to restart it for any reason, you can use the following command:

sudo systemctl restart firewalld

This will stop and then start the firewall, allowing any changes or updates to take effect immediately.

Using the firewall-cmd Command

Another approach to check the firewall status in CentOS 7 involves using the firewall-cmd command, which is a command-line frontend for the firewalld service. Follow the steps below:

• Open a terminal or SSH session to the CentOS 7 system.
• Type the following command to view the firewall status:

sudo firewall-cmd --state

If the firewall is running, you will see the output "running." If it is not running, the output will be "not running."

Checking if Ports are Open

It is essential to verify if specific ports are open on the firewall, especially when configuring services that require network access. You can use the following steps to check if a port is open:

• Open a terminal or SSH session to the CentOS 7 system.
• Type the following command to list the open ports:

sudo firewall-cmd --list-ports

This command will display a list of all the open ports on the firewall. If the output is empty, it means that no ports are open.

If you want to check if a specific port is open, you can use the following command:

sudo firewall-cmd --query-port=PORT_NUMBER/PROTOCOL

Replace "PORT_NUMBER" with the actual port number you want to check, and "PROTOCOL" with the appropriate network protocol used by the service (e.g., tcp or udp).

Example

To check if port 80 (HTTP) is open, use the following command:

sudo firewall-cmd --query-port=80/tcp

If the port is open, the command will return "yes." If it is closed, the output will be "no."

Using GUI Tools

If you prefer to use a graphical user interface (GUI) to check the firewall status in CentOS 7, there are several tools available that provide a graphical representation of the firewall configuration. Some popular options include:

• FirewallD: A default firewall management tool that comes with CentOS 7. You can access it by going to Applications > Internet > Firewall.
• GNOME Firewall Configuration: A graphical tool accessible through the CentOS 7 system settings. You can open it by going to Settings > Firewall.

These GUI tools allow you to view and modify the firewall rules, check the status, and manage network zones.

Exploring Deeper: Understanding the iptables Command

While CentOS 7 uses the firewalld service as the default firewall management tool, it is worth noting that it is built upon the iptables framework. Iptables is a powerful command-line utility that allows more advanced configuration and fine-grained control over the firewall rules.

If you have extensive knowledge of iptables and want to dig deeper into the firewall configuration, you can use the following command to check the status:

sudo iptables -L

This command will display the current firewall rules specified using iptables. However, please note that managing the firewall directly with iptables requires a strong understanding of networking concepts and the associated risks. It is recommended to use the higher-level tools mentioned earlier, such as firewalld or firewall-cmd, unless you have specific requirements.

By following the methods described above, you can easily check the firewall status in CentOS 7 and ensure that your system is protected by an active and properly configured firewall.

Checking Firewall Status in Centos 7

Firewall is a crucial component of the security infrastructure in a CentOS 7 server. It controls incoming and outgoing network traffic, protecting the system from unauthorized access. Checking the firewall status is an essential step to ensure the server's security.

To check the firewall status in CentOS 7, follow these steps:

• Login to your CentOS 7 server as a root user or a user with sudo privileges.
• Execute the following command in the terminal:

  systemctl status firewalld

• If the firewall is active, the output will show the service status as "active" and display additional information about the firewall rules and zones.
• If the firewall is inactive, the output will show the service status as "inactive" and confirm that the firewall is not running.

By following these simple steps, you can quickly check the firewall status in CentOS 7. It is recommended to keep the firewall active and regularly monitor it to ensure the server's security.

Frequently Asked Questions

Here are some commonly asked questions about how to check the firewall status in Centos 7:

1. How can I check if the firewall is enabled or disabled in Centos 7?

To check if the firewall is enabled or disabled in Centos 7, you can use the following command:

sudo firewall-cmd --state

If the firewall is enabled, the command will return "running." If the firewall is disabled, the command will return "not running."

It is important to note that you need root or sudo privileges to run this command.

2. How can I view the status of individual firewall services in Centos 7?

To view the status of individual firewall services in Centos 7, you can use the following command:

sudo firewall-cmd --list-services

This command will display a list of all the services that are currently allowed through the firewall. You will see services like ssh, http, https, etc., if they are allowed.

If the command returns empty, it means that no services are currently allowed through the firewall.

3. How can I check the status of a specific port in the firewall of Centos 7?

To check the status of a specific port in the firewall of Centos 7, you can use the following command:

sudo firewall-cmd --list-ports

This command will display a list of all the ports that are currently allowed through the firewall. You will see ports like 22, 80, 443, etc., if they are allowed.

If the command returns empty, it means that no ports are currently allowed through the firewall.

4. How can I check the status of a specific service in the firewall of Centos 7?

To check the status of a specific service in the firewall of Centos 7, you can use the following command:

sudo firewall-cmd --query-service=<service_name>

Replace <service_name> with the actual name of the service you want to check. For example, if you want to check the status of the SSH service, you would use:

sudo firewall-cmd --query-service=ssh

The command will return "yes" if the service is allowed through the firewall, and "no" if it is not.

5. How can I check the status of a specific zone in the firewall of Centos 7?

To check the status of a specific zone in the firewall of Centos 7, you can use the following command:

sudo firewall-cmd --get-active-zones

This command will display a list of all the active zones in the firewall, along with the interfaces assigned to each zone. You can see the zones like public, home, or internal.

If you want to check the status of the default zone, you can use the following command:

sudo firewall-cmd --get-default-zone

The command will return the name of the default zone, such as "public."

Checking the firewall status in CentOS 7 is a quick and straightforward process. By using the 'systemctl' command, you can easily determine if the firewall is enabled or disabled on your system. This information is crucial for ensuring the security of your CentOS 7 server.

To check the firewall status, open the terminal and type 'systemctl status firewalld'. If the firewall is active, the command will display 'active (running)'. On the other hand, if the firewall is inactive, the output will show 'inactive (dead)'. This simple check allows you to ascertain the current state of your firewall and take necessary actions to enhance the security of your CentOS 7 server.