Implementing a bridging-level firewall
The Drawbridge
Firewalls are typically implemented as routers,but it doesn’t have to be that way. Bridging packet filters have a number of advantages,and you can add them to your network at a later stage without changing the configuration of your network components.
Linux has earned a reputation as an excellent firewall platform. The kernel has a powerful Netfilter/ IPtables-based packet filter. In a traditional firewall scenario, Netfilter resides on a router, where it subdivides the network into two or more subnets. But adding a firewall to an established network can involve changing the network infrastructure. This effort can result in IP address changes and modifications to access controls for internal services. It is far simpler to add a bridge. Bridges reside in layer 2 of the OSI reference model and normally inspect MAC addresses rather than IP addresses (see the box titled “Building Bridges”). Linux can leverage this capability in a clever way to add transparent firewalling to a network. Of course, the bridge evaluates packets from the higher protocol layers (IP addresses, TCP ports) in its role as a firewall. But the hosts on the network will not notice a thing, unless they attempt to send illegal packets.
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
US / Canada
UK / Australia
News
-
Mozilla VPN Now Available for Linux
The promised subscription-based VPN service from Mozilla is now available for the Linux platform.
-
Wayland and New App Menu Coming to KDE
The 2021 roadmap for the KDE desktop environment includes some exciting features and improvements.
-
Deepin 20.1 has Arrived
Debian-based Deepin 20.1 has been released with some interesting new features.
-
CloudLinux Commits Over 1 Million Dollars to CentOS Replacement
An open source, drop-in replacement for CentOS is on its way.
-
Linux Mint 20.1 Beta has Been Released
The first beta of Linux Mint, Ulyssa, is now available for downloading.
-
Manjaro Linux 20.2 has Been Unleashed
The latest iteration of Manjaro Linux has been released with a few interesting new features.
-
Patreon Project Looks to Bring Linux to Apple Silicon
Developer Hector Martin has created a patreon page to fund his work on developing a port of Linux for Apple Silicon Macs.
-
A New Chrome OS-Like Ubuntu Remix is Now Available
Ubuntu Web looks to be your Chrome OS alternative.
-
System76 Refreshes the Galago Pro Laptop
Linux hardware maker has revamped one of their most popular laptops.
-
Dell Will Soon Enable Privacy Controls for Linux Hardware
Dell makes it possible for Linux users to disable webcams and microphones.