Hamy - The IT Guy
Overview LuCi is a very popular OpenWrt web interface. For an average user, LuCi is probably one of the main deciding factors between giving OpenWrt a try in the first place, or moving on to another user friendlier firmware like DD-WRT . If you’re an advanced user however, most of the times you may find yourself adjusting settings either through UCI or by editing the config files manually.…
Overview We all know what OpenWrt is. The amazing Linux distro built specifically for embedded devices. What you can achieve with a rather cheap router running OpenWrt, is mind-boggling. OpenWrt also gives you a great control over its build system. For normal cases, you probably don’t need to build OpenWrt from source yourself. That has been done for you already and all you need to do, is to…
Overview Why Dante? In the previous post , I talked about why we might need a SOCKS proxy at all, and how we can properly setup a secure one using only stunnel. That approach is fine and all, but it still suffers from some limitations. The most important of which are: UDP relaying is not supported. Advanced SOCKS options like BIND or UDPASSOCIATE is not available. Only suited for personal use and…
Why using SOCKS There are times in which setting up a complete VPN tunnel might be an overkill (or not be an option at all). For example, assume the followings: You don’t want to tunnel all the traffic, just want to do so for your browsers. Your OS is running under a limited account and doesn’t allow creation of tun interfaces. Your provider does not allow setting up a tun device. You…
Overview We all know how awesome stunnel is, but setting it up properly on Ubuntu (and on most other distros, really), can be a little tricky. This post is dedicated to show you how to properly install and configure this magnificent piece of software on Ubuntu. For this, I’ll be using Ubuntu 18.04 Server . There is a good chance however that the same procedure (maybe with slight…
Overview In this post we’re going to talk about how to run the amazing stunnel program on your Android device properly. Later, this would allow us to setup a lot of cool things like: Wrapping OpenVPN traffic with it Using it as a SOCKS VPN Adding proper IMAPS/SMTPS support to our old email apps … For this, we’re not going to use the old and very limited SSLDroid . It’s a…
My data, my precious data… is gone. Overview This is a story about how I lost my data when trying to prevent it by backing it up. Even though there were numerous other factors in play, I take full responsibility for what happened. I have written this article hoping that it could save someone else from the same situation. No one should ever experience the loss of his/her data. 7 days and 10…
This post provides a more in-depth look at the obfs4proxy-openvpn script. You don’t need to fully read it to make use of the script, but it will help you to get the most out of it. Overview After my initial post about obfs4 on how to hide any TCP traffic and an example for hiding SSH traffic , it’s now time to do so for OpenVPN. For this, I have written a Bash script to do the job.…
Overview In the previous post , I talked about pt-spec-v1 and obfs4 and explained how obfs4proxy can be setup and used outside of Tor . You are advised to read it to get the most out of this post. In this post I’m going to give you a real example of obfs4proxy being used to obfuscate SSH traffic. For this, I’ll be using two Ubuntu 18.04 Servers. But with a little to no adjustment, any…
Overview In this post, I’m going to give you the information necessary to be able to use obfs4 protocol not just for wrapping Tor traffic, but for virtually any other TCP traffic as well. Doing so for the previous Pluggable Transports of this kind (namely obfs2 , obfs3 and ScrambleSuit ) was rather simple. obfsproxy program written python, already supports being run in standalone (or so…
Overview In the previous post, I talked about Network IP Fragmentation , what it is and why it’s needed (You are advised to read it before continuing). I also covered the so called PMTUD Black hole effect. Fixing a PMTUD Black hole is a multistep process, and it starts with finding the correct MTU/MRU of your link. Now as I’ve discussed, every path can have its own unique MTU/MRU…
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Overview In this post, I’m going to talk about what IP fragmentation is, how it works and why it’s needed. And while learning that, we’re going to touch on subjects like OSI Layers / PDU / MTU / MRU and PMTUD . Knowledge about them is required for truly understanding IP fragmentation process and troubleshooting network connection issues in general. OSI model This is basically a…
Although this article mainly targets OpenVPN TAP driver installation issue, The problem is likely not limited to that specific driver. You may want to continue reading and give the very easy solution at the end of the article a try. Recently I had to install OpenVPN on a system running Windows XP (Don’t ask). The installation went smoothly up until TAP driver installation and then suddenly…
Much has been changed since my last post about LUKS remote unlock workaround (Particularly, The bug is finally fixed in cryptsetup 2:2.0.2-1ubuntu1.1 and no more workaround is needed). This, is the updated version on how to set things up properly. UPDATE: Well, it turned out that while the previous bug is fixed, another one still exists. You can find the required workaround for it at the end of…
I like Kaspersky anti-virus, and I use it regularly… (Not on my own PC mind you, but on the clients) While I do believe they provide the best anti-virus in the market, I am not a fan of most of their other products . That goes for the Firewall, Safe Browsing, SSL Hijacking, and of course their newest addition, Secure Connection… In a previous post , I talked about how to optimize…
No Postfix installation is complete without OpenDKIM and OpenDMARC . While some people go for all-in-one solutions that does all of these for them with a single command or two, the rest of us rather to be our own bosses and set things up manually and carefully based on our needs, so we can troubleshoot it if when things go wrong. This however, is easier to be said than done. In this post, rather…
The Tail of Windows UAC Windows systems… I’m not particularly fond of them anymore. I do believe however that the introduction of UAC, while not perfect 1 , was a step in the right direction. We’re all familiar with UAC by now; introduced in Windows Vista and got better by newer versions. While the technical details are complex, the basic concept is simple enough. Microsoft…
This Post is now outdated. Particularly the said bug is finally fixed. Updated version is available HERE Unfortunately the bug-fixed version of cryptsetup package, caused incompatibilities with the previous version of the workaround. If you see this message when remotely unlocking your server: “ /bin/cryptroot-unlock: line 192: 2: parameter not set ” Run this command instead to boot…
Recently I was in need of setting up some windows clients to connect to my OpenVPN server. This server running on Linux, uses a specific MTU value (let’s say 1400) to ensure maximum compatibility with different clients over different links. In addition to the OpenVPN process itself, the kernel must also know about the correct MTU so packet size could be adjusted before reaching the tun/tap…
In the previous post , I talked about OpenVPN TCP and UDP tunnels and why you should not be using TCP. In this post, I’m going to talk about optimizing the said tunnels to get the most out of them. Believe it or not, the default OpenVPN configuration is likely not optimized for your link. It probably works but its throughput could possibly be improved if you take the time to optimize it. A…
Spoiler alert: You most likely would want to use UDP tunneling! An OpenVPN tunnel runs over IP and can encapsulates VPN traffic into either a UDP or a TCP connection. To understand the pros and cons of each, we first need to have an understanding of them both. TCP Transmission Control Protocol is the dominant protocol there is for most daily stuff happening on a network. It has some very…
Green as it’s cool, green as it’s quite, just like the trees. You’d think it’s all good and perfect. It’s also supposed to consume way less power. Yay, greener planet… Except… When i started buying them in bulk, 500GB was a lot and a 32MB cache size seemed to be preferable to 16MB which the blue caviar offered at the time. From time to time when i was in…