Set up Firewalld on Centos 7

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 dynamic managed firewall with support for network/firewall zones.

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. These services are xml configuration files with information of a service entry. xml configuration files are stored in the /usr/lib/firewalld/services/ and /etc/firewalld/services/ directories.

1. 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
2. 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
3. Open port 25 (SMTP) and port 465 (SMTPS)
   # firewall-cmd --zone=dmz --add-service=smtp --permanent
# firewall-cmd --zone=dmz --add-service=smtps --permanent
4. 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
5. 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
6. Reload the firewall to implement your changes
   # firewall-cmd --reload
7. List your firewall rules
   # firewall-cmd --list-all

Protect your server with FirewallD

When you set up FirewallD on CentOS 7, you ensure a higher server safety level. FirewallD features graphical configuration tool (firewall-config) and command line tool (firewall-cmd).

For more advice or assistance setting up FirewallD on CentOS 7, contact HOSTAFRICA today.