January 9, 2026
Plug-and-pray port wars
QtNat – Open you port with Qt UPnP
New tool auto‑opens home router ports; half cheer speed, half scream security
TLDR: QtNat automates opening router ports via UPnP to make apps reachable from outside your home network. Comments explode over convenience vs. security, with critics calling UPnP a major hole and others seeking approval workflows or key-based alternatives—big implications for gamers, P2P tools, and remote access apps.
QtNat just dropped: a tiny C++ library built with Qt 6 that automatically opens your home router’s door using UPnP (a protocol that lets devices set up port forwarding). Translation: it makes peer‑to‑peer apps, games, and remote tools visible from the outside without you poking through router menus. The dev says it’s tested locally and invites everyone to try it; code’s on GitHub.
The crowd? Spicy. The loudest chorus is the security alarm. One top comment sneers, “People still use UPnP?” and says it’s the first thing they disable. Another calls UPnP a “major security hole,” citing OpenWRT—popular custom router firmware—leaving it out by default. Cue the paranoia memes: “Universal Plug & Pray” and “UPnP = Uninvited People ‘n’ Pirates.”
On the flip side, devs who build multiplayer or remote features are eyeing the convenience, but even they’re side‑eyeing the implementation. One critic says this is a “solved problem” with existing libraries, then dunks on QtNat’s approach for dragging “~30,000 lines of headers to generate a static XML.” Ouch. Another commenter pitches a middle ground: make UPnP requests show up as pending on your router so you can approve them per device, like a permissions pop‑up.
Then there’s the security‑but‑usable crowd: “Give me a trusted server with keys so only my devices can find me,” a non‑UPnP alternative that feels like secure matchmaking. Verdict: slick idea, polarizing execution, and a classic battle of convenience vs. caution.
Key Points
- •QtNat is a C++ library built with Qt 6 to automate NAT port mapping via UPnP.
- •It creates port forwarding rules at runtime on compatible routers to expose local services.
- •Discovery uses an M-SEARCH multicast request to locate a UPnP server and retrieve a description file via QNetworkAccessManager.
- •The description file is parsed to identify device types and protocol versions (1 or 2).
- •Mapping requests are sent as HTTP payloads generated with inja; successful replies set status to NAT_ADD.