March 11, 2026
Simu-late Night Fights
Show HN: I built an ISP infrastructure emulator from scratch with a custom vBNG
One dev built a “fake ISP” at home—cheers, side‑eye, and spicy nitpicks
TLDR: A developer built a virtual ISP lab with a custom virtual gateway that resets automatically and can run on a laptop. Commenters split between praising the DIY learning, recommending existing tools like Mininet and NetBox, and raising real‑world scaling questions—making it a must‑watch thread for anyone curious how ISPs actually work.
An indie builder just dropped a home‑grown ISP lab—think a pretend internet provider you can reset every 6 hours, tweak with a simulator.config.json file, and run locally with Vagrant. The star gadget? A custom virtual Broadband Network Gateway (vBNG), the traffic cop of an ISP—only this one lives on your laptop. The community? Oh, they turned it into a roast, a pep rally, and a study group all at once.
The strongest take came fast: why roll your own when tools already exist? One commenter swore by Mininet, the classroom‑friendly network simulator, calling the DIY route brave but… maybe unnecessary. Another pushed for NetBox—an open‑source “source of truth” for network maps—to replace hand‑rolled configs, basically yelling “use Lego bricks, not clay.” On the other side, builders rallied: doing it from scratch is the ultimate crash course, and this lab’s reset‑by‑CI and plug‑and‑play setup screams hacker‑friendly.
Amid the sparring, a newcomer asked the wholesome question everyone loves: is this real‑world software minus the expensive hardware? Meanwhile, a pro dropped a practical bomb: how do you pick the right customer circuit at scale? Expect rabbit holes in the NANOG archives. Memes flew—“Comcast won’t call me back, so I built my own internet”—but the verdict is split: reinventing or re‑learning?
Key Points
- •A custom vBNG-based ISP infrastructure emulator was built from scratch.
- •The lab environment auto-resets every 6 hours and can be reset via CI triggers.
- •Traffic simulation parameters are managed through simulator.config.json.
- •The lab can be run locally inside a VM using Vagrant.
- •The project focuses on emulating Broadband Network Gateways (BNGs).