Apps similar to ferm include Shorewall, which is free and open source. Other options are ConfigServer Firewall, Advanced Policy Firewall, iptablesbuild and foomuuri. In total there are five Firewalls like ferm for Linux.
The Shoreline Firewall, more commonly known as “Shorewall”, is high-level tool for configuring Netfilter. You describe your firewall/gateway requirements using entries in a set of configuration files. Shorewall reads those configuration files and with the help of the iptables...
A Stateful Packet Inspection (SPI) firewall, Login/Intrusion Detection and Security application for Linux servers.
United Kingdom
Server-based firewall. Reacts to attacks with intelligent abilities to detect malicious attempts to enter and reacting by blocking the IP temporarily. Repeated hits will ban the IP completely.
iptablesbuild is effectively a configuration manager for iptables. It is intended to manage iptables configurations in a centralized location for multiple systems.
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