iptables alternatives

nftables is supposed to replace netfilter as the primary interface of network filtering. It is available since Linux kernel 3.13. Both netfilter and nftables have been co-authored by Patrick McHardy.

Douane is an application firewall that blocks unknown or unwanted traffic. It provides a more fine-grained filtering as it looks at the combination of application and used network ports. This is useful when allowing common browse traffic on port 80 and 443. Instead of all applications being able to use this port, only the ones that are granted access will be able to do so. When a new connection is not trusted yet, Douane will ask to allow or deny the traffic stream.

This script could be useful for system and network administrators that want to learn about better defending the network against lots of network packets. The Linux kernel has a default configuration that is optimized for performance. To further secure it, changes need to be made to these kernel settings. The Anti-DDoS tool will help with setting up the configuration.

The primary goal of this solution is to prevent ARP spoofing by other computers on the local network. It uses a whitelist and blocks all other systems sending possible malicious ARP requests (e.g. with spoofing attack).

This tool provides a centralized method to distribute ipset blacklists.

A tool like Assimilator can be of great help to 'normalize' all firewall rules into one place. Especially when a company uses different firewalls, each with their own syntax and specifics. Assimilator will then simplify the way firewall rules are created and managed.

Tools like opensvp can be used to test the strength of a configuration from the outside. It makes it a good tool for penetration testing and security assessments. While people may feel safe to have a firewall in place, it might be unknowingly vulnerable to several attacks on protocol level. This tool helps with finding these weaknesses.

Port knocking tools typically hide services from the outside world by requesting a 'secret'. This secret is like a special way of knocking on a door, to let others know you can be trusted. It does not replace a password or other method of authentication, yet adds another layer to it.

This security tool enables the user to perform hop enumeration (similar to traceroute). Instead of sending actual packets, it uses an established TCP connection.

360-FAAR is a tool written in Perl to parse policies and logs from firewalls. It can compare firewall policies and translate between a policy and log data. Supported firewalls include Checkpoint FW1, Cisco ASA, and Netscreen ScreenOS.

Chiron is a security assessment framework for IPv6. It provides several modules including an IPv6 scanner, IPv6 Local Link, IPv4-to-IPv6 proxy, IPv6 attack module, and IPv6 proxy. These modules help to perform an assessment, like a penetration test.

The tool uses IPv6 extension headers to create a headers chain. This may allow evading security devices like IDS, IPS, and firewalls. Due to the flexibility of the framework, the tool can also be used to perform fuzzing of the IPv6 stack of a device.

Knock implements the principle of port knocking. It does so by using libpcap to sniff network traffic on interfaces and then use that to see if it matches a predefined sequence of steps.

LPFW is the abbreviation for LeoPard FloWer and is an application firewall for Linux.

OpenSnitch is a tool based on Little Snitch, a macOS application level firewall. All outgoing connections are monitored and the user is alerted when a new outgoing connection occurs. This allows the user to detect and block any unwanted connections.