When working on subnet addressing, we often have to look up and double-verify any address we deal with. Some of you have been doing this for so long that you can make all these calculations off the top of your head. But for most of us, it’s a cumbersome and…
Let’s consider the following scenario: you have a Linux host that has more than one network interface, both are routable and both are up and running. How do you determine which interface or route is used when trying to reach another host? In other words the routing table looks like…
This is the last of four posts related to dnsmasq; it covers the basics on how to set up your own DHCP server on your network. For reference, here are the previous dnsmasq posts on DNS caching, a read-only TFPT server, and DNS server. Set Up To install dnsmasq you…
In two previous blog posts we talked about Dnsmasq’s DNS caching and read-only TFTP server set up. Continuing with a third dnsmasq-related post, we’ll talk about how to set up a DNS server in your network. Set Up Literally, all you have to do is install dnsmasq on a host:…
In a previous post we talked about dnsmasq’s DNS caching capabilities. Here we’ll talk about the Trivial File Transfer Protocol server included in the dnsmasq utility. Note that this is a read-only TFTP server, and the reason it’s included in dnsmasq is that if you combine it with its DHCP…
Dnsmasq is Linux utility which provides DNS, DHCP, TFTP and DNS caching capabilities. It’s a very lightweight service, is available for most Linux distribution, and has found wide adoption for Android as well as OS X users. In this post, we’ll talk about the DNS caching part. Installation This could…
In a previous post I talked about the WiFi Protected Access (WPA) Supplicant logs for PreShared Key (PSK) authentication and how to make sense of them. The reality is that although the logs are useful, you will be intimidated if you don’t know what to look for. This post builds…
iptables is a Linux utility that is often considered difficult or intimidating to use. In this post, I will try to break down how to use it so that it is more digestible. The good thing about iptables is that it can slice and dice the network traffic in any…
There are many reasons you might want to direct your traffic through a proxy. To name a few: It’s the only way to get out of a restricted network To avoid being tracked To use DNS behind proxy Most popular applications have native options to configure proxy server settings. Browsers…
I have talked about nmap in past blog posts; for example here and here. Despite having written about nmap before, I am writing about it once more because it is such a valuable, versatile, and powerful tool for every network engineer. In the previous post I talked about some basic…