Can Firewalld and iptables Run Concurrently?

The question of whether Firewalld and iptables can coexist on a system arises often among system administrators. Both tools are crucial for managing firewall rules, but their coexistence is not typically recommended due to potential conflicts and redundancy. This article explores the compatibility of these two firewall management tools and provides guidance on how to ensure smooth operation of your network security.

Understanding Firewalld and iptables

Firewalld is a dynamic firewall management tool that operates with a zone-based approach. Zones are collections of services and rules designed for different network environments, such as public, trusted, and drop zones. Firewalld manages iptables rules in the background to enforce these policies. On the other hand, iptables is a more traditional and lower-level tool that manages firewall rules directly without the use of zones or services.

Despite their differences, both tools serve the same fundamental purpose: to control traffic based on rules. Both tools work with the Netfilter framework to perform network-related operations such as packet filtering, network address translation (NAT), and port translation. However, running both tools simultaneously can lead to confusion and unexpected behavior.

Potential Issues

If Firewalld and iptables are active at the same time, one tool may modify iptables rules, leading to conflicts. This can result in overlapping rules, errors, and unpredicted outcomes such as unexpected packet drops or routing issues. Such conflicts can make network troubleshooting more challenging and can inadvertently block or redirect legitimate traffic.

Recommendations

To avoid these potential conflicts and ensure a clear and controlled environment, it is generally advisable to use only one of the two tools. Here are some steps to choose and implement the suitable firewall management tool for your system:

Choosing Firewalld

If you decide to use Firewalld, you should disable iptables to prevent any conflicts. You can achieve this using the following commands:

# Stop and disable iptablessystemctl stop iptablessystemctl disable iptables# Enable and start Firewalldsystemctl enable firewalldsystemctl start firewalld

By following these steps, you can ensure that Firewalld manages all firewall rules without interference from iptables.

Choosing iptables

If you prefer using iptables, you should disable and stop Firewalld to prevent conflicts. The corresponding commands are as follows:

# Stop and disable Firewalldsystemctl stop firewalldsystemctl disable firewalld# Enable and start iptablessystemctl enable iptablessystemctl start iptables

In this scenario, iptables directly manages firewall rules without any interference from Firewalld.

In Summary

While Firewalld and iptables can coexist, it is generally more advisable to use only one of them for managing your firewall rules. This approach ensures clarity and control over your network security settings, reducing the risk of conflicts and maintaining the integrity of your firewall configurations.

Conclusion

Both Firewalld and iptables are powerful tools designed for managing firewall rules, but using them simultaneously is not recommended due to potential conflicts. By choosing one tool and disabling the other, you can ensure a smooth and effective network security setup. For more detailed information and best practices regarding network security, consult official documentation and maintain up-to-date knowledge on security best practices.