Firewalld uses runtime and permanent configuration options, which you can manage using firewall-cmd.
In this tutorial, I will explain how to solve "firewall-cmd: command not found" error on RHEL/CentOS 7.
To fix this error, we need to install firewalld
Now, start firewalld service and enable it to auto-start at system reboot.
In this tutorial, I will explain how to solve "firewall-cmd: command not found" error on RHEL/CentOS 7.
To fix this error, we need to install firewalld
sudo yum install firewalld
Now, start firewalld service and enable it to auto-start at system reboot.
# sudo systemctl start firewalld
# sudo systemctl enable firewalld
# sudo systemctl status firewalld
Open/Close Port
Firewall rule settings are managed by firewalld service daemon. A command-line client called firewall-cmd can talk to this daemon to update firewall rules permanently.
Open port
For Example, To open a port TCP/443 permanently, use following commands.
Close above port
Adding and Removing Services in Firewalld
By default, firewalld comes with pre-defined services, if we want to add any specific services so need adds using the command. like ftp, ssh, etc...
For example, the following commands will add or remove SSH services.
For example, the following commands will add or remove FTP services.
Firewall rule settings are managed by firewalld service daemon. A command-line client called firewall-cmd can talk to this daemon to update firewall rules permanently.
Open port
For Example, To open a port TCP/443 permanently, use following commands.
# firewall-cmd --zone=public --add-port=443/tcp --permanent
# firewall-cmd –reload
Close above port
# firewall-cmd --zone=public --remove-port=443/tcp --permanent
# sudo firewall-cmd --reload
Adding and Removing Services in Firewalld
By default, firewalld comes with pre-defined services, if we want to add any specific services so need adds using the command. like ftp, ssh, etc...
For example, the following commands will add or remove SSH services.
# firewall-cmd --zone=public --add-service=ssh
# firewall-cmd --zone=public --remove-service=ssh
# firewall-cmd --zone=public --list-services
For example, the following commands will add or remove FTP services.
# firewall-cmd --zone=public --add-service=ftp
# firewall-cmd --zone=public --remove-service=ftp
# firewall-cmd --zone=public --list-services
