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
News
-
KaOS 2022.06 Now Available With KDE Plasma 5.25
The newest iteration of KaOS Linux not only adds the latest KDE Plasma desktop but sets LibreOffice as the default.
-
Manjaro 21.3.0 Is Now Available
Manjaro “Ruah” has been released and includes the latest Calamares installer, GNOME 42, and much more.
-
SpiralLinux is a New Linux Distribution Focused on Simplicity
A new Linux distribution, from the creator of GeckoLinux, is a Debian-based operating system with a focus on simplicity and ease of use.
-
HP Dev One Linux Laptop is Now Available for Pre-Order
The System76/HP collaboration Dev One laptop, geared toward developers, is now available for pre-order.
-
NixOS 22.5 Is Now Available
The latest release of NixOS with a much-improved package manager and a user-friendly graphical installer.
-
System76 Teams up with HP to Create the Dev One Laptop
HP and System76 have come together to develop a new laptop, powered by Pop!_OS and aimed toward developers.
-
Titan Linux is a New KDE Linux Based on Debian Stable
Titan Linux is a new Debian-based Linux distribution that features the KDE Plasma desktop with a focus on usability and performance.
-
Danielle Foré Has an Update for elementary OS 7
Now that Ubuntu 22.04 has been released, the team behind elementary OS is preparing for the upcoming 7.0 release.
-
Linux New Media Launches Open Source JobHub
New job website focuses on connecting technical and non-technical professionals with organizations in open source.
-
Ubuntu Cinnamon 22.04 Now Available
Ubuntu Cinnamon 22.04 has been released with all the additions from upstream as well as other features and improvements.