Jason Hite jasonmhite

A Short IPv6 Guide for Home IPv4 Admins

This guide is for homelab admins who understand IPv4s well but find setting up IPv6 hard or annoying because things work differently. In some ways, managing an IPv6 network can be simpler than IPv4, one just needs to learn some new concepts and discard some old ones.

Let’s begin.

First of all, there are some concepts that one must unlearn from ipv4:

Concept 1

Error

$ sudo apt-get update
Err:1 http://archive.ubuntu.com/ubuntu focal InRelease
Temporary failure in name rerolution

$ host google.com
;; connection timed out; no servers could be reached

Contemporary Python Packaging

This document lays out a set of Python packaging practices. I don't claim they are best practices, but they fit my needs, and might fit yours.

Validity

This document has been superseded as of January 2023.

This was written in July 2020, superseding this gist from 2019.

Guide to PROGMEM on ESP8266 and Arduino IDE

Intro

On low memory devices like the arduino and esp8266 you do not want strings to be stored in RAM. This occurs by default on these systems. Declare a string const char * xyz = "this is a string" and it will use up RAM.

The solution on these devices is to allow strings to be stored in read only memory, in Arduino this is the PROGMEM macro. Most of my experience is with the ESP8266 which is a 32bit micros controller. This device stores PROGMEM data in flash. The macro PROGMEM on ESP8266 is simply

#define PROGMEM   ICACHE_RODATA_ATTR

Disclaimer: Please follow this guide being aware of the fact that I'm not an expert regarding the things outlined below, however I made my best attempt. A few people in IRC confirmed it worked for them and the results looked acceptable.

Attention: After following all the steps run gdk-pixbuf-query-loaders --update-cache as root, this prevents various gdk-related bugs that have been reported in the last few hours. Symptoms are varied, and for Cinnamon the DE fails to start entirely while for XFCE the icon theme seemingly can't be changed anymore etc.

Check the gist's comments for any further tips and instructions, especially if you are running into problems!

Screenshots

Results after following the guide as of 11.01.2017 13:08:

Setting up Pi Zero OTG - The quick way (No USB keyboard, mouse, HDMI monitor needed)

More details - http://blog.gbaman.info/?p=791

For this method, alongside your Pi Zero, MicroUSB cable and MicroSD card, only an additional computer is required, which can be running Windows (with Bonjour, iTunes or Quicktime installed), Mac OS or Linux (with Avahi Daemon installed, for example Ubuntu has it built in).
1. Flash Raspbian Jessie full or Raspbian Jessie Lite onto the SD card.
2. Once Raspbian is flashed, open up the boot partition (in Windows Explorer, Finder etc) and add to the bottom of the config.txt file dtoverlay=dwc2 on a new line, then save the file.
3. If using a recent release of Jessie (Dec 2016 onwards), then create a new file simply called ssh in the SD card as well. By default SSH i

	echo "dtoverlay=i2c-rtc,ds3231" >> /boot/config.txt

	cat <<EOF > /etc/udev/rules.d/55-rtc-i2c.rules
	#/lib/udev/rules.d/50-udev-default.rules:SUBSYSTEM=="rtc", ATTR{hctosys}=="1", SYMLINK+="rtc"
	#/lib/udev/rules.d/50-udev-default.rules:SUBSYSTEM=="rtc", KERNEL=="rtc0", SYMLINK+="rtc", OPTIONS+="link_priority=-100"

	# I2C RTC, when added and not the source of the sys clock (kernel), is used
	ACTION=="add", SUBSYSTEMS=="i2c", SUBSYSTEM=="rtc", KERNEL=="rtc0", ATTR{hctosys}=="0", \\
	RUN+="/sbin/hwclock '--rtc=\$root/\$name' --hctosys", \\
	RUN+="/sbin/logger --tag systemd-udevd 'System clock set from i2c hardware clock \$name (\$attr{name})'"

	#!/bin/bash

	# This script allows you to chroot ("work on")
	# the raspbian sd card as if it's the raspberry pi
	# on your Ubuntu desktop/laptop
	# just much faster and more convenient

	# credits: https://gist.github.com/jkullick/9b02c2061fbdf4a6c4e8a78f1312a689

	# make sure you have issued

	#!/bin/bash

	# Runs the specified command (provided by the first argument) in all tmux panes
	# in every window. If an application is currently running in a given pane
	# (e.g., vim), it is suspended and then resumed so the command can be run.
	all-panes()
	{
	all-panes-bg_ "$1" &
	}

	docinfo.html
	Documentation.md
	pics/