4 ms·

Reverse Engineering a Mysterious UDP Stream in My Hotel (2016)

220 points by bayesnet 10mo ago

kstrauser 10mo ago
I LOLed at the ending. Nicely done! I appreciate people posting negative results, too. The journey is the interesting part, and I like the humanity of saying "welp, at least now I know".
- mingus88 10mo ago
  Yeah 99/100 times it’s gotta be mundane but wouldn’t it be interesting to spoof that traffic and play anything you wanted in the elevator?
  - kstrauser 10mo ago
    "That would be wrong. You totally should not do that." But yes, absolutely!
- eru 10mo ago
  Though in this case, it's actually more of a positive result? The author figured out what the data was. It just wasn't very exiting.
gkbrk 10mo ago
Author here, hi :^)
- contingencies 10mo ago
  Since you appear to be Turkish what's your favourite Turkish food that is poorly known outside of the country? Also don't miss https://subseacables.blogspot.com/2025/12/fully-diverse-100g-waves-sofiaistanbul.html https://subseacables.blogspot.com/2025/12/fully-diverse-100g...
  - gkbrk 10mo ago
    "poorly known outside the country" rules out the main foods I like. I love a good Kuymak [1] though, I think that's not too well known. [1]: https://en.wikipedia.org/wiki/Kuymak https://en.wikipedia.org/wiki/Kuymak
    - contingencies 10mo ago
      Nice, haven't tried that. Found a local cafe which looks very well run where it's a feature. On the list for next year! Happy New Year!
- nicelunch 10mo ago
  Hi! Do you happen to have that elevator music saved? I'm curious what it sounded like.
  - gkbrk 10mo ago
    I had it saved, but it was 3-4 computers ago. I don't think I still have it, and if I did I wouldn't know where. Aside from the article, I only found these scripts on my disk related to this project. listen_2046.py and send_2046.py https://gist.github.com/gkbrk/445929a854051203ee31afc7495c5a87 https://gist.github.com/gkbrk/445929a854051203ee31afc7495c5a...
    - Sophira 10mo ago
      I'm curious now, did you develop the sending program at the same hotel, and if so, did it work? (My guess is probably not, but you might DoS the other stream while you're sending your own.)
  - kogasa240p 10mo ago
    Lol asked the same thing on his website
- bayesnet 10mo ago
  Thank you for writing one of my favorite blog posts of all time! I am curious: What is your favorite thing you’ve written?
dang 10mo ago
Related. Others? Reverse engineering a mysterious UDP stream in my hotel (2016) - https://news.ycombinator.com/item?id=34912300 https://news.ycombinator.com/item?id=34912300 - Feb 2023 (179 comments) Reverse engineering a mysterious UDP stream in my hotel (2016) - https://news.ycombinator.com/item?id=26633792 https://news.ycombinator.com/item?id=26633792 - March 2021 (86 comments) Reverse Engineering a Mysterious UDP Stream in My Hotel (2016) - https://news.ycombinator.com/item?id=16197436 https://news.ycombinator.com/item?id=16197436 - Jan 2018 (15 comments) Reverse Engineering a Mysterious UDP Stream in My Hotel - https://news.ycombinator.com/item?id=11744518 https://news.ycombinator.com/item?id=11744518 - May 2016 (181 comments)
- yunnpp 10mo ago
  It's just as good in 2026 - 2d. Imagine Santa delivering his goods and hearing a mysterious UDP stream and wondering, "Is my supply chain being disrupted?", only to then realize that it was just the owners' TV spying on him after it was left on standby instead being completely turned off.
Dilettante_ 10mo ago
This is the shortest, yet still fully complete example of an article that scratches that itch. Awakening the "intellectual curiosity", documenting the steps, and finding the actual end of the matter. The mundanity of the revelation is like the icing on the cake.
- deadbabe 10mo ago
  I wish there was a whole book of just random compiled stories like this.
schmuckonwheels 10mo ago
I was expecting to see a post bemoaning the lack of encryption on the elevator music...
runtimepanic 10mo ago
This is the kind of curiosity that leads to the most interesting findings. Hotels are a perfect storm of shared networks, opaque vendor integrations, and “it just works” assumptions. A mysterious UDP stream could be anything from Chromecast-style discovery to IPTV control or some half-documented vendor heartbeat. What’s usually more revealing than the payload is the pattern: broadcast vs unicast, frequency, and who responds. Also a good reminder of how much ambient network noise we’re all swimming in without noticing.
7e22v837278gb1p 10mo ago
Good hotel room hacking entertainment is provided in-house, in this case.
mikesale 10mo ago
omg this is so my vibe! I used to read corrupted database files for a living and it was soooo much fun.
naikrovek 10mo ago
Site is down, I think. :(
jiscariot 10mo ago
I've read this one before, but this time it really hit home in how unlike most of the modern AI-emoji-filled-cringy-heading-20-page blog slop, it is. Very refreshing.
VoidWhisperer 10mo ago
Archive link as it seems the site is down: https://archive.is/afYvQ https://archive.is/afYvQ
- gkbrk 10mo ago
  Oops, picked a bad week to migrate from Cloudflare Pages to something custom in Rust.
StayTrue 10mo ago
https://web.archive.org/web/20251230193736/https://www.gkbrk.com/hotel-music https://web.archive.org/web/20251230193736/https://www.gkbrk...
cryptoegorophy 10mo ago
Web server down? Can’t access.
JSR_FDED 10mo ago
I love how tiny and to the point the Python scripts are. I bet if you asked AI to make these today the comments would be longer than these entire scripts. But I’m too bored by the idea to try it :-)
bobske4 10mo ago
expecting a rick roll here

220 points by bayesnet 10mo ago

I LOLed at the ending. Nicely done! I appreciate people posting negative results, too. The journey is the interesting part, and I like the humanity of saying "welp, at least now I know".

mingus88 10mo ago
Yeah 99/100 times it’s gotta be mundane but wouldn’t it be interesting to spoof that traffic and play anything you wanted in the elevator?
- kstrauser 10mo ago
  "That would be wrong. You totally should not do that." But yes, absolutely!
eru 10mo ago
Though in this case, it's actually more of a positive result? The author figured out what the data was. It just wasn't very exiting.

gkbrk 10mo ago

Author here, hi :^)

contingencies 10mo ago
Since you appear to be Turkish what's your favourite Turkish food that is poorly known outside of the country? Also don't miss https://subseacables.blogspot.com/2025/12/fully-diverse-100g-waves-sofiaistanbul.html https://subseacables.blogspot.com/2025/12/fully-diverse-100g...
- gkbrk 10mo ago
  "poorly known outside the country" rules out the main foods I like. I love a good Kuymak [1] though, I think that's not too well known. [1]: https://en.wikipedia.org/wiki/Kuymak https://en.wikipedia.org/wiki/Kuymak
  - contingencies 10mo ago
    Nice, haven't tried that. Found a local cafe which looks very well run where it's a feature. On the list for next year! Happy New Year!
nicelunch 10mo ago
Hi! Do you happen to have that elevator music saved? I'm curious what it sounded like.
- gkbrk 10mo ago
  I had it saved, but it was 3-4 computers ago. I don't think I still have it, and if I did I wouldn't know where. Aside from the article, I only found these scripts on my disk related to this project. listen_2046.py and send_2046.py https://gist.github.com/gkbrk/445929a854051203ee31afc7495c5a87 https://gist.github.com/gkbrk/445929a854051203ee31afc7495c5a...
  - Sophira 10mo ago
    I'm curious now, did you develop the sending program at the same hotel, and if so, did it work? (My guess is probably not, but you might DoS the other stream while you're sending your own.)
- kogasa240p 10mo ago
  Lol asked the same thing on his website
bayesnet 10mo ago
Thank you for writing one of my favorite blog posts of all time! I am curious: What is your favorite thing you’ve written?

dang 10mo ago

Related. Others? Reverse engineering a mysterious UDP stream in my hotel (2016) - https://news.ycombinator.com/item?id=34912300 https://news.ycombinator.com/item?id=34912300 - Feb 2023 (179 comments) Reverse engineering a mysterious UDP stream in my hotel (2016) - https://news.ycombinator.com/item?id=26633792 https://news.ycombinator.com/item?id=26633792 - March 2021 (86 comments) Reverse Engineering a Mysterious UDP Stream in My Hotel (2016) - https://news.ycombinator.com/item?id=16197436 https://news.ycombinator.com/item?id=16197436 - Jan 2018 (15 comments) Reverse Engineering a Mysterious UDP Stream in My Hotel - https://news.ycombinator.com/item?id=11744518 https://news.ycombinator.com/item?id=11744518 - May 2016 (181 comments)

yunnpp 10mo ago
It's just as good in 2026 - 2d. Imagine Santa delivering his goods and hearing a mysterious UDP stream and wondering, "Is my supply chain being disrupted?", only to then realize that it was just the owners' TV spying on him after it was left on standby instead being completely turned off.

Dilettante_ 10mo ago

This is the shortest, yet still fully complete example of an article that scratches that itch. Awakening the "intellectual curiosity", documenting the steps, and finding the actual end of the matter. The mundanity of the revelation is like the icing on the cake.

deadbabe 10mo ago
I wish there was a whole book of just random compiled stories like this.

schmuckonwheels 10mo ago

I was expecting to see a post bemoaning the lack of encryption on the elevator music...

runtimepanic 10mo ago

This is the kind of curiosity that leads to the most interesting findings. Hotels are a perfect storm of shared networks, opaque vendor integrations, and “it just works” assumptions. A mysterious UDP stream could be anything from Chromecast-style discovery to IPTV control or some half-documented vendor heartbeat. What’s usually more revealing than the payload is the pattern: broadcast vs unicast, frequency, and who responds. Also a good reminder of how much ambient network noise we’re all swimming in without noticing.

7e22v837278gb1p 10mo ago

Good hotel room hacking entertainment is provided in-house, in this case.

mikesale 10mo ago

omg this is so my vibe! I used to read corrupted database files for a living and it was soooo much fun.

naikrovek 10mo ago

Site is down, I think. :(

jiscariot 10mo ago

I've read this one before, but this time it really hit home in how unlike most of the modern AI-emoji-filled-cringy-heading-20-page blog slop, it is. Very refreshing.

VoidWhisperer 10mo ago

Archive link as it seems the site is down: https://archive.is/afYvQ https://archive.is/afYvQ

gkbrk 10mo ago
Oops, picked a bad week to migrate from Cloudflare Pages to something custom in Rust.

StayTrue 10mo ago

https://web.archive.org/web/20251230193736/https://www.gkbrk.com/hotel-music https://web.archive.org/web/20251230193736/https://www.gkbrk...

cryptoegorophy 10mo ago

Web server down? Can’t access.

JSR_FDED 10mo ago

I love how tiny and to the point the Python scripts are. I bet if you asked AI to make these today the comments would be longer than these entire scripts. But I’m too bored by the idea to try it :-)

bobske4 10mo ago

expecting a rick roll here