Tags: IPtables

Why Is the Kernel Community Replacing iptables with BPF?

Author Note: this is a post by long-time Linux kernel networking developer and creator of the Cilium project, Thomas Graf The Linux kernel community recently announced bpfilter, which will replace the long-standing in-kernel implementation of iptables with high-performance network filtering powered...
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network traffic
Learn how to use IPtables to alter how your traffic is manipulated as it arrives at your server.

Redirecting Network Traffic: Part 2

In the previous article, I looked at how to use the clever redir utility to listen out for inbound traffic on a particular port on a host and then forward that traffic onward somewhere else. Here, I’ll briefly describe some other approaches to manipulating traffic that may suit your needs. IPTables...
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This screenshot of /etc/protocols shows the correct protocol names to use in iptables rules; get details from Carla Schroder in this tutorial.

How to Write iptables Rules for IPv6

We US-ians have been sheltered from the exhaustion of IPv4 addresses, but they have run out. IPv6 networks are up and running, so we have no excuses for not being IPv6 literate. Today our scintillating topic is iptables rules for IPv6, because, I am sad to report, our faithful IPv4 iptables rules...
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Iptables Basics

Yesterday I tweeted “hey, I learned some stuff about iptables today”! A few people replied “oh no, I’m sorry”. iptables has kind of a reputation for being hard to understand (and I’ve also found it intimidating) so I wanted to write down a few things I learned about iptables in the last few days. I...
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Learn more about how to set up a sensible firewall with iptables in this tutorial.

Building Linux Firewalls With Good Old Iptables: Part 2

When last we met we reviewed some iptables fundamentals. Now you'll have two example firewalls to study, one for a single PC and one for a LAN. They are commented all to heck to explain what they're doing. This is for IPv4 only, so I'll write up some example firewalls for IPv6 in a future...
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In this two-part series, Carla Schroder shows how to run iptables from the command line, so you can set policies on what to deny or allow.

Building Linux Firewalls With Good Old Iptables: Part 1

Of course, we still need firewalls on our computers, even though that is not a subject we see much in these here modern times. There are Linux and BSD firewalls, prefab firewalls on commercial hardware from little to big that are most likely based on an open source firewall and a multitude of GUI...
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Shorewall is an open source firewalling tool that makes the task of network security easier.

An Introduction to the Shorewall Firewall Tool

Linux is well known for being a highly secure platform. One of the reasons for said security is the Netfilter system. For those that don’t know, Netfilter is a framework, provided by the Linux kernel, that allows for various networking operations, such as packet filtering, network address...
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