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Comment by _-david-_ | Hacker News Reader

>This concerns UDP traffic on port 9000-65535.

Does anybody know what usually runs on those ports?

That's 56,536 different ports. Half of everything (that uses UDP), more or less.

I would expect 95%+ of TCP traffic to run on 22 (ssh), 25(smtp), 53(dns), 80(http), 443(https) plus another handful of lower than 1000 ports. Even common dev ports (3000,5000,8080) are below 9000. I don't think that's much different for UDP. Even most games probably rely on something <10,000.

> I don't think that's much different for UDP.

It is, because of the way that UDP is typically used for different applications than TCP. While there are a few old, well known TCP/UDP pairs like 53, UDP is more often used with a dynamic port assignment scheme sometimes with a coordinating TCP protocol - such as SIP/RTP for VoIP that uses >16k, WebRTC, etc. A lot of games uses ports above 10k. https://help.generationesports.com/hc/en-us/articles/3600611...

I think games.

Hetzner is a popular host for game servers.

Besides games, I think many AV things, including VOIP and perhaps WebRTC (definitely UDP, less sure about port number). Possibly also HTTP/3; the server picks the UDP port number IIUC.

Isn't it most things that aren't a well-known service?

It's interesting that 9000 is the starting port for Ethereum consensus clients, although the participation rate does not seem to be affected.

Source ports of DNS reflection attacks, presumably.

Online games (MMOs, shooters, etc) come to mind

MMOs over UDP?

Absolutely

That's the preferred protocol for ultra-real-time games because a few ms ago is not helpful information to spend time recovering. A sufficiently fast-moving MMO could apply

What MMOs use UDP? Asking sincerely because I have never seen one.

Anything with real time communications like an FPS would use UDP as stale action data is mostly useless. The latest state of is all that matters.

Most such games will either layer their own streaming channel atop UDP for guaranteed ordered delivery of important messages or use a separate TCP socket as well.

You must not be looking very hard, pretty much every game engine uses UDP as the network transport. There are some notable exceptions like Java Minecraft.

all of them, its been like that for a long time. im resurrecting an old mmo, and even then it was UDP.

WoW, FFXIV, ESO, GW2, etc

Some might use TCP for login and character select, but its UDP while playing.

WoW is 100% TCP. idk about the rest.

MMOs often have TCP connections for things like chat and services like auction house (often even HTTP microservices), but most of the gameplay is still UDP.

I fear e.g. wireguard is affected.

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