Yosef Weissmann alxbnct

Setting up NixOs with LUKS encrypted root

Here are my working notes on getting a system up and running.

WARNING: You can run into a hidden problem that will prevent a correct partition setup and /etc/nixos/configuration.nix from working: if you are setting up a UEFI system, then you need to make sure you boot into the NixOS installation from the UEFI partition of the bootable media. You may have to enter your BIOS boot selection menu to verify this. For example, if you setup a NixOS installer image on a flash drive, your BIOS menu may display several boot options from that flash drive: choose the one explicitly labeled with “UEFI”.

References

I used these resources:

Getting started with Linux kernel development

Prerequisites

The Linux kernel is written in C, so you should have at least a basic understanding of C before diving into kernel work. You don't need expert level C knowledge, since you can always pick some things up underway, but it certainly helps to know the language and to have written some userspace C programs already.

It will also help to be a Linux user. If you have never used Linux before, it's probably a good idea to download a distro and get comfortable with it before you start doing kernel work.

Lastly, knowing git is not actually required, but can really help you (since you can dig through changelogs and search for information you'll need). At a minimum you should probably be able to clone the git repository to a local directory.

Linux Mail Server

In this guide, I will show you how to make a Linux Mail Server in fast and easy way. This guide was taken from tiq's tech-blog for recent version, Linux distro I using is Ubuntu 20.04 LTS

Certificate

Make sure you have Certificate and Key file ready to use.

You can use existing Web Server SSL certificate, since we going to use same domain, example.com.

If you plan to use mx.example.com or mail.example.com you need create another one for these.

ipvtap over wifi for libvirt

ipvtap is similar to macvtap, but works over wifi too, since it uses the same mac address as the wifi interface.

libvirt doesn't support ipvtap, so we have to configure everything manually. Important data we need before we start:

the name of the wifi interface, wlan0 in my case (it's already connected - use NM or networkd+iwd).
the mac address of the wifi interface (it must be the same in the guest too)

On the host:

Renew GPG key

Given that your key has expired.

$ gpg --list-keys
$ gpg --edit-key KEYID

Use the expire command to set a new expire date:

This is a quick guide of the commands we use to sign someone's GPG key in a virtual key signing party.

Note: The steps cover only the technical aspects of signing someone's key. Before signing someone's key, you must verify their identity. This is usually done by showing government-issued ID and confirming the key's fingerprint

The commands will work for both GPG and GPG2.

I use Julian's key for the examples. His key id is 2AD3FAE3. You should substitute with the appropriate key id when running the commands.

Signing the key

List the keys currently in your keyring: gpg --list-keys.

Build git from source code

1) Go to https://git-scm.com/ and check out the latest version of Git

Currently, the latest version is 2.18.0. Download and extract it and go to the folder of the source code:

wget https://mirrors.edge.kernel.org/pub/software/scm/git/git-2.18.0.tar.gz
tar xf git-2.18.0.tar.gz
cd git-2.18.0/

Installing i3-gaps

Dependencies

i3-gaps has some packages that are required for it to work so install these things:

sudo apt install libxcb1-dev libxcb-keysyms1-dev libpango1.0-dev libxcb-util0-dev libxcb-icccm4-dev libyajl-dev libstartup-notification0-dev libxcb-randr0-dev libev-dev libxcb-cursor-dev libxcb-xinerama0-dev libxcb-xkb-dev libxkbcommon-dev libxkbcommon-x11-dev autoconf xutils-dev libtool automake

You also need to install libxcb-xrm-dev, but I got Unable to locate package libxcb-xrm-dev when trying to install from the apt repositories on Ubuntu 16.04. If this happens to you, just install it from source using these commands:

mkdir tmp

	proc printf*(format: cstring): cint {.importc, header: "<stdio.h>".}

	proc fprintf*(stream: File, format: cstring): cint {.importc, header: "<stdio.h>".}

	proc sprintf*(str: var cstring, format: cstring): cint {.importc, header: "<stdio.h>".}

	proc vsprintf*(str: var cstring, format: cstring, arg: varargs[typed, `$`]): cint {.importc, header: "<stdio.h>".}

	proc vfprintf*(stream: File, format: cstring, arg: varargs[typed, `$`]): cint {.importc, header: "<stdio.h>".}

	;;; The Y Combinator explained in scheme.
	;;; with credits to:
	;;; https://mvanier.livejournal.com/2897.html
	;;; Status: WIP

	(define fibonacci
	(lambda (n)
	(cond ((= n 0) 0)
	((= n 1) 1)
	(else (+ (fibonacci (- n 1)) (fibonacci (- n 2)))))))