Setting up FirewallD on CentOS 7 is a relatively easy and straightforward process. FirewallD is a firewall management tool that CentOS 7 servers offer by default. It provides a dynamically managed firewall with support for network/firewall zones. If you're configuring firewalls and server security, these related guides can help you manage Linux firewall tools and strengthen your server's security posture:
- Configuring CentOS 8 Firewall with firewalld & firewall-cmd
- Setting Up a Simple Firewall in Linux
- Convert CentOS 7 FirewallD to iptables
How to set up FirewallD on CentOS 7
Here we show you how to set up FirewallD on CentOS 7 if you’re running a web server, SSH on port 7022, and mail server. FirewallD uses services and zones instead of iptables rules and chains. FirewallD services are xml configuration files with information about a service entry. xml configuration files are stored in the /usr/lib/firewalld/services/ and /etc/firewalld/services/ directories.
- Change the default zone:
Run # firewall-cmd --get-zones to list all the available zones Run # firewall-cmd --get-default-zone to list the default zone Change the default zone by entering # firewall-cmd --set-default-zone=dmz
- Add permanent service rules for HTTP and HTTPS to the dmz zone
Run # firewall-cmd --get-services to list all available services. Enter # firewall-cmd --zone=dmz --add-service=http --permanent and # firewall-cmd --zone=dmz --add-service=https --permanent
- Open port 25 (SMTP) and port 465 (SMTPS)
# firewall-cmd --zone=dmz --add-service=smtp --permanent # firewall-cmd --zone=dmz --add-service=smtps --permanent
- Open, IMAP, IMAPS, POP3, and POP3S ports:
# firewall-cmd --zone=dmz --add-service=imap --permanent # firewall-cmd --zone=dmz --add-service=imaps --permanent # firewall-cmd --zone=dmz --add-service=pop3 --permanent # firewall-cmd --zone=dmz --add-service=pop3s --permanent
- Since the SSH port is changed to 7022, you need to remove the SSH service (port 22) and open port 7022:
# firewall-cmd --remove-service=ssh --permanent # firewall-cmd --add-port=7022/tcp --permanent
- Reload the firewall to implement your changes:
# firewall-cmd --reload
- List your firewall rules:
# firewall-cmd --list-all
Protect your server with FirewallD
When you set up FirewallD on CentOS 7, you are ensuring a higher safety level for your server. FirewallD features a graphical configuration tool (firewall-config) and a command line tool (firewall-cmd). For more advice or assistance setting up FirewallD on CentOS 7, contact HostAfrica today.
