dns – Techno Wizardry

There were a few services that I ran that I wanted to be able to access from both inside my home network and outside my home network. If I was inside my home network, I wanted to route directly to the service, but if I was outside I needed to be able to route traffic through a proxy that would then route into my home lab. Additionally, I wanted to support SSL on all my services for security using cert-manager

Since my IPv4 addresses differ inside my network vs outside, I need to use split-horizon DNS to respond with the correct DNS query. Split-horizon DNS refers to the DNS on one horizon (inside the network) showing different results than outside the network.

DNS is the protocol that converts domain names like “technowizardry.net” into the IP address of the server that will respond like “144.217.181.222”. In DNS, domain names actually are supposed to end with a period. For example, the URL of this website is not “www.technowizardry.net”, but it’s actually “www.technowizardry.net.” Notice the period at the end.

Where does this come from? If you look at a DNS packet in a packet capture, you’ll see that each query looks something like this:

The queried domain starts right where I’ve highlighted in the above picture. Domain names are separated by each period. In this example, I have 3 separate domain parts: [“www”, “technowizardry”, “net”]. The byte sequence looks like:

Tag: dns

Split Horizon DNS with external-dns and cert-manager for Kubernetes

Domain names actually end with a period and why that might subtly break your system