• Networking

    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

  • Chart: iptables Command Matrix

    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

  • Persistence: Making iptables Changes Stick

    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.

  • Helpful Tips (iptables)

    Here are a few helpful tips related to rule and route testing.

    Don't Forget to Flush!

    If you make changes to ip rules, ip routes, or iptables and wish to utilize them prior to

  • iptables Commands

    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.

    The following

  • Linux Routing Table Architecture

    placeholder for routing table architecture discussion
  • Follow the (ip) Rules

    Hopefully, you have already read and/or understand these concepts:

  • Netmask/Genmask Conversion Table

    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

  • Introduction to Split Gateways

    Having explained the process behind gateway routes in the previous article, what is a split

  • Linux Network Routing Best Practices

    Here are some brief concepts to keep in mind when adding new routes and routing tables.

    Master Routing Table Best Practices

    High level concepts to keep in mind when adding new

  • Linux Networking F.A.Q.

    What is the purpose of routing tables?

    Routing tables inform the Linux kernel where to find destinations on a network. They describe information such as which network interface to send

  • Split Gateway Tutorial

    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

  • Netmask Filtering Deep Dive

    What is a Netmask (or Genmask)? And why is understanding it so important when it comes to network routing?

  • Routers, Routes, Subnets, and Netmasks

    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

  • A Brief History of Linux Networking

    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.

  • Routing and Filtering Network Traffic

    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

  • Linux Firewall Management Tools Overview

    Two systems built-in to Ubuntu manage network routing: route (a legacy system) and ip route. Both use the same underlying code, yet report networking context a

  • Routes, Rules, and Tables

    This category primarily covers:

    1. iptables, iproute, and netfilter
    2. Routing network traffic
    3. How Linux structures network
  • Exposing the Myth of "Best" VPN Services

    This article explores why "Best" lists of VPN providers are not useful.

    There are many, many VPN service providers on the market. Hundreds. No joke. VPNs are "in."

  • How the NSA Monitors VPNs

    Did you know in the United States, the NSA (National Security Agency) routinely monitors all internet traffic coming in or out of the United States?1 Were you aware

  • Gateways

    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

  • A Layman's Guide to Networking Cryptography

    A Layman's Guide to Networking Cryptography

    This article explains common network cryptographic concepts in plain-English.


  • Who Watches the (VPN) Watchers?

    How does someone who is not a VPN subject-matter expert choose a VPN provider? Often by reading reviews of various service providers. Yet, how can one tell the difference between a real review

  • Reviewing the VPN Reviewers

    Which VPN service providers are worthy of your time and which should you avoid like The Plague?

    There are so many VPN providers these days (over 300), and so many "reviewers," it has

  • The Great Global VPN Swindle

    Although I'm a big proponent of VPNs, the industry has become littered with mis-information and outright shams, creating a mixed environment when it comes to advertised claims of privacy

  • WireGuard

    WireGuard is the "new kid on the block" in the world of VPNs.

    Protocol adoption in the VPN world is a very slow process. Yet a relatively recent upstart is garnering a lot of attention:

  • Secure Tunneling IP Network Protocol IDs

    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

  • Linux ACL File Systems

    Virtually any file system you apply to a Linux operating system (such as Ubuntu) will have ACL capabilities. ACL is an acronym for "Access Control List." In simple terms, it means the file system

  • Split VPNs

    Split VPN Gateway

    A split gateway divides outgoing network traffic between two or more gateways. This is most common with traffic traveling from a private network out to the

  • Choosing the Right VPN Provider

    The process of selecting a VPN provider should not be taken lightly. The more one is concerned with privacy or anonymity, the fewer good choices there are. VPNs are a crucial component of a

  • Do You Really Need (or Want) a VPN?

    Contemplating signing up for a Virtual Private Network (VPN)? Why? The truth is most people don't need them, most of the time. Here's how to determine if it truly makes sense for you.

  • VPN (Virtual Private Network) F.A.Q.

    What does VPN mean?

    VPN is an abbreviation for Virtual Private Network.

    What is a Virtual Private Network (VPN)?

    A VPN is a secure, virtual

  • Bibliography for VPN Articles

    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

    Bibliography for VPN

  • Virtual Private Networks (VPNs)

    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

  • iptables and iprules

    Primarily covers iptables, ipchains, and ip rules. It also touches on ufw (Uncomplicated FireWall), and nftables ("NetFilter Tables"), the successor

  • Policy Based Routing

    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

  • Is Your VPN Helping or Hurting You?

    If you could sum up the purpose of a Virtual Private Network (VPN) in one word, what would it be? My choice: Integrity.

    Of course, I'm talking about data integrity. But, what

  • Security Implications of Samba Access to non-ACL File Systems

    Several processes control the flow of data through a Samba-managed network connection. Ironically, the most important of them has nothing to do with networking.

  • Bibliography (Networking Articles)

    Andreasson, Oskar. Iptables Tutorial 1.2.1. Chapter 6: Traversing of tables and chains.

    Andreasson, Oskar. 2006.

  • Special Routing Use-Case Scenarios (iproute2)

    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.

    Dropping Packets

    Here are

  • Route and Netstat

    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

  • iproute and Routing Tables

    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

  • How VPNs Work - Part 1: Overview

    This article is Part 1 in a 3-part series on how Virtual Private Networks (VPNs) work. Part 1 delves into the nuances of VPNs at a high-level, scratching the surface on the inner workings of VPN

  • Demystifying IKE/IKEv2

    Demystifying IKE/IKEv2

    IKEv2 is a security protocol that facilitates cryptographic symmetric key exchanges between endpoints.

  • How VPNs Work - Part 3: Encryption and Authentication

    This article is Part 3 in a series of three (3) articles about how Virtual Private Networks (VPNs) work. While I get into some technical details, the intent is to scratch the surface just enough

  • What Is IPsec?

    This document is a comprehensive, high-level overview of what IPsec is and how it works.

    IPsec is a flexible network security framework that may be applied to a number of different use

  • Combining a VPN and Smart DNS

    Thinking of combining a Virtual Private Network (VPN) service with a Smart DNS service? If you'll be running both services on the same device, before you leap forward with your plans it's wise to

  • Mitigating Risk: Combining Privacy Services

    This article is about digital privacy and specifically, safeguarding your privacy online through the use of Virtual Private Networks and Domain Name System masking

  • Locked Out: Accessing Geo-fenced Content

    The entertainment industry has developed numerous techniques to restrict end users' ability to access digital content based on geographic location. End users trying to dodge these geographic

  • 5 Ways to Install OpenVPN on Ubuntu 14.04, 16.04, 18.04

    OpenVPN is an open source Virtual Private Network (VPN) software solution that rivals similar commercially available products. It allows you to use PKI (Public Key Infrastructure) and SSL/TLS

  • OpenVPN and OpenSSL: Partners in Security

    This article examines the relationship between OpenVPN and OpenSSL, why the former depends on the latter, and why it's important to remain cognizant of software version numbers

  • OpenVPN Version List and Changelog

    Table comparing the complete list of all OpenVPN versions. See below for pertinent notes.

    DNS Alphabet Soup: Dedicated, Dynamic, Smart

    Dedicated DNS. Dynamic DNS. Smart DNS. What the heck are these things???

    Many consumers get confused between these very distinct services. It's not their fault. I blame the marketing

  • How VPNs Work - Part 2: Protocols

    This article is Part 2 in a series of articles about how Virtual Private Networks (VPNs) work. Part 1 of the series,

  • Critical Vulnerability Impacts Nearly All VPN Software

    A newly discovered security vulnerability exists in most modern operating systems which allows a malicious actor to hijack an active TCP-based VPN connection, without the need to break its