Category: Network Notes

bookmark_borderPi-Hole Error: Could not update local repository. Contact Support.

Posted on by Tony

When you are running Pi-Hole for the first time, you might run into an error that reads:

Could not update local repository. Contact Support.

This can be for a couple of different reasons, but these are the ones that have been most effective:

  1. Verify that you chose the right interface when installing Pi-Hole. For instance, I chose the ethernet interface on the installation process. When it went to install, it assumed the internet was on this interface. I reran the installer, chose the WiFi interface, and it worked. Alternatively, connect it via the ethernet interface and that too should work.
  2. If you are running this on a new install, or what you believe to be a new install, try running this command:

pi@raspberrypi:~ $ sudo git clone -q –depth 1 https://github.com/pi-hole/pi-hole.git /etc/.pihole

If it returns this, it’s an update problem, not a new install problem:

fatal: destination path ‘/etc/.pihole’ already exists and is not an empty directory.

Good luck!

bookmark_borderTips and Tricks: Blocking DNS requests via Iptables

Posted on by Daniel Cid

Iptables has to be one of the tools that I use the most on my day to day work. The default firewall tool chain on Linux has a lot of options to filter pretty much any traffic you wish.

In this Tips and Tricks, we will show you how to block DNS requests (domain names + request types) via iptables. Enjoy!

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bookmark_borderInspecting DNS traffic via tcpdump

Posted on by Daniel Cid

If you ever wondered what is going on at the DNS level on your computer (or network), tcpdump can be a useful tool for you.

TCPdump basics

Tcpdump is a tool that allows you to inspect any packet (TCP, UDP, etc) and its content as they pass through an interface through the libpcap module. The syntax is very simple, but the basics of the command require the network interface name, the protocol and the restrictions of what you are trying to inspect (more on that later):

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bookmark_borderBlocking HTTP requests via Iptables for a specific domain

Posted on by Daniel Cid

In a previous article, we showed how to block specific domains at the DNS level using iptables. Today, we will expand into that and show how to also block HTTP requests for a specific domain (or URL) in there.

Iptables String Matching

Iptables string matching is very powerful and easier to use than the hex-string module we used before. When you specify -m string –string, it will activate the string module and inspect at the packet content for the keyword you are looking for.

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bookmark_borderBinding multiple IPv6 addresses automatically

Posted on by Daniel Cid

Most servers get a IPv6 range (/64) by default. That means that you have millions of IP addresses to use for whatever you feel like. However, assigning them manually to your interfaces can be a bit painful.

Assigning all /64 IPv6 addresses with 1 command

However, there is a trick with the ip route command that allows you to link your /64 to the local interface and cover all of them automatically:

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