About TTR Networks
TTR Networks — trying to remember networks — is a free, hands-on place to learn how networks actually work: switching and IP addressing, routing with OSPF and BGP, firewalls and NAT, IPv6, VPNs, data-centre fabrics and the day-to-day work of running them. It is operated by MNIG Pty Ltd, an Australian company, and it isn't affiliated with any vendor, software project, standards body or internet registry.
The name is honest: networking is a lot to keep in your head. The lessons are written the way we'd want to relearn a topic ourselves — the reason something exists first, then a working configuration, then what it looks like when it breaks.
Every lesson is built in a real lab
Nothing in a lesson is a mock-up. Each one is built around a lab that we actually run:
- Routers: VyOS (as a full virtual machine) and FRRouting containers, the same software many real networks run.
- Hosts and tools: Debian Linux with the standard tools —
ip,ping,traceroute,tcpdump,dig. - Supporting services where a lesson needs them, such as a local IRRd routing registry or an RPKI-to-router (RTR) server.
The configuration in a lesson is the configuration that was committed in the lab, and every command output is copied from a real run — trimmed where it repeats, but never edited. Each lesson says when it was last tested and on which software versions, so you can tell if it has gone stale. Where an example comes from the real internet (a traceroute, say), every address is replaced with documentation addresses and the lesson says so.
Some lessons start from configurations used on real production networks. Those are sanitised before they're used: no secrets, no real addresses, AS numbers or names. All examples use the address blocks and AS numbers set aside for documentation (RFC 5737, RFC 3849 and RFC 5398), so nothing you copy will clash with a real network.
How the lessons are written
The lessons are written with the help of AI tools and reviewed by a person before they're published. AI helps with drafting and with turning lab notes into readable explanations; the labs, the configurations and the output are real, and automated checks run over every lesson before it can be published:
- every lesson, diagram and quiz is validated against the site's schema, and every annotation must point at real lines of its configuration (the site won't build if any of this fails);
- every FRR configuration is checked by FRR's own parser in the test suite.
That still doesn't make the lessons infallible. A lab isn't your network, explanations can be wrong or go out of date, and quiz answers can have mistakes. Treat the site as reference material and check anything important against vendor documentation and the RFCs.
Found a mistake?
Please tell us. Every page has a "Report an issue" link that opens an email with the page already filled in, or you can write to contact@ttrnetworks.com. Corrections are the most useful thing a reader can send.
Where to start
New to networking? The Start here path goes from switches and IP addresses to a working router and the two routing protocols everything else builds on. Know what you're looking for? Search the lessons, browse the glossary, or keep a cheat sheet open while you work.