[Solved] What are some good open source firewalls for Linux?

I'd recommend checking out Firewalld. It's the default on Fedora and offers a dynamic firewall management tool with support for network/firewall zones. Its ability to change settings without stopping the current connections is a lifesaver. Plus, the documentation is pretty robust, and it integrates well with GUI tools if you're into that.

1. Install Firewalld (Fedora/CentOS/RHEL):

   sudo dnf install firewalld

2. Start and enable Firewalld:

   sudo systemctl start firewalld sudo systemctl enable firewalld

3. Allow HTTP traffic:

   sudo firewall-cmd --permanent --add-service=http sudo firewall-cmd --reload

nftables is the way to go, in my opinion. It's the next evolution of iptables, providing a more efficient framework and easier syntax. It's designed to replace iptables, and it offers better performance and more features. The ability to use inet family for both IPv4 and IPv6 is a huge plus. There's a bit of a learning curve, but the community is growing, and the documentation is improving rapidly. Definitely, the future of Linux firewalls.

1. Install nftables (Debian/Ubuntu):

   sudo apt-get update sudo apt-get install nftables

2. Start nftables service:

   sudo systemctl enable nftables sudo systemctl start nftables

3. Add a basic rule (allowing SSH):

   sudo nft add rule inet filter input tcp dport 22 accept

Have you looked into UFW (Uncomplicated Firewall)? It's incredibly user-friendly and is essentially a front-end for iptables. Great for people who are new to firewall concepts or those who prefer a simpler interface. The syntax is straightforward, making it easy to configure. Plus, it's widely used, so community support is quite strong.

Don't overlook iptables itself, despite the newer options available. It's the traditional tool for Linux and gives you full control over your network traffic. It can be complex, but it's incredibly powerful if you're willing to learn its syntax. The community and online resources are vast, given its long-standing use.

For something a bit different, pfSense, which is based on FreeBSD, can actually be used on Linux servers through virtualization. It's not just a firewall; it's a full-featured security appliance. This might be overkill for some, but its web interface is top-notch, and it offers features like VPN, traffic shaping, and more. Plus, the community and documentation are excellent.

Shorewall might not be as well-known as some others, but it's worth a look. It's a front-end for iptables and offers a high level of abstraction, making complex configurations more manageable. It's got great documentation and supports a wide range of features, including IPv6, QoS, and more.

VyOS is another option to consider. It's an open-source network OS that includes firewall functionality. It's not strictly a firewall tool; it's a router OS but offers advanced firewall capabilities, VPN, and more. It's CLI-based, so there's a bit of a learning curve.

Thanks for all the detailed suggestions! To clarify, I'm looking for a firewall solution for a general server setup primarily used for file sharing. It seems like UFW or Firewalld might be the most straightforward choices for my needs.