A brief, high-level introduction to Linux networking architecture. Explains how the Linux kernel manipulates network traffic using a top-down approach and basic framework to route
Have you ever wondered why Linux network management is so confusing? You need only make a cursory review of the history of Linux networking tools to understand how it got this way.
Andreasson, Oskar. Iptables Tutorial 1.2.1. Chapter 6: Traversing of tables and chains. https://www.frozentux.net/iptables-tutorial/chunkyhtml/c962.html.
Andreasson, Oskar. 2006.
A traditional router stores network route information in routing tables. A routing table is a map of a network. Linux uses a policy based routing system, aptly called a
We will begin the detailed discussion of the first component of the Routing Policy DataBase (RPDB) triad: routes (the other two components are ip rules and ip
Now that you have a basic understanding of Linux network routing, it's time to delve into some interesting things you can do with this information.
This section describes the use of alternative tools to the iproute2 suite for viewing the status of a network. They may be old, but route and netstat can still be useful
Having explained the process behind gateway routes in the previous article, what is a split
Hopefully, you have already read and/or understand these concepts:
A critical component of managing routes is understanding the role netmasks play in managing routing traffic. More commonly known as the netmask, the sub-network mask or
What is a Netmask (or Genmask)? And why is understanding it so important when it comes to network routing?
Routers manage routes. Some routers act as gateways. A gateway is a forwarding router that forms a bridge between local and remote networks. A gateway is required when sending a packet
Thinking of creating split routes or split gateways? This article is a basic introduction, but it is a hands-on tutorial and will walk you through the building blocks of
Routing tables inform the Linux kernel where to find destinations on a network. They describe information such as which network interface to send
Here are some brief concepts to keep in mind when adding new routes and routing tables.
High level concepts to keep in mind when adding new
It's much easier for most people to reference charts of netmask/genmask/CIDR values vs. trying to remember them (though some common masks such as 0 and 255 are easy
There are a large number of filters you may apply to your server's network rules via the iptables command. Some of these are found in extensions to iptables.
Here are a few helpful tips related to rule and route testing.
If you make changes to ip rules, ip routes, or iptables and wish to utilize them prior to
One of the challenges of iptables, routes, and rules (iprules) is making changes to them permanent. Any changes you make on-the-fly only last until the next system restart.
Chart of the most commonly used iptables rule syntax, demonstrating command syntax along with the tables and chains where each command may be utilized. The table scrolls
This is a list of sources I found useful while writing my comprehensive guides on VPNs for Small Business Owners, Home Office Workers, and Split VPNs
VPN is an abbreviation for Virtual Private Network.
A VPN is a secure, virtual
Tunnels in the IT networking world refers to a communications channel connecting two (2) networks or devices when those devices reside on different local networks or sub-nets. A tunnel
I.T. networking is a HUGE topic, and I am by no means going to cover every concept, tool, and scenario. What you will find here is a series of mini-guides designed to help you gain a basic
This category primarily covers:
Primarily covers iptables, ipchains, and ip rules. It also touches on ufw (Uncomplicated FireWall), and nftables ("NetFilter Tables"), the successor
This category contains articles about Virtual Private Networks (VPNs), such as what they are, why you may or may not need or want one, how they function, and how to pick the best VPN service