Can't cast local file on arch linux.

[NicklasSpendler]

I get this when I try and cast a file:
Serving local file(s). 192.168.0.15 - - [28/Mar/2025 21:07:44] "GET /?loaded_from_catt HTTP/1.1" 206 - video/x-matroska - 274.50 MB 192.168.0.15 - - [28/Mar/2025 21:07:44] "GET /?loaded_from_catt HTTP/1.1" 206 - video/x-matroska - 274.50 MB 192.168.0.15 - - [28/Mar/2025 21:07:44] "GET /?loaded_from_catt HTTP/1.1" 206 - video/x-matroska - 274.50 MB

I've allowed range on my firewall using:

sudo ufw allow 45000:47000/tcp

and status now shows:
`To Action From

---

45000:47000/tcp ALLOW Anywhere
45000:47000/tcp (v6) ALLOW Anywhere (v6) `

I am quite new to Linux, so I am not sure if I am missing something

[medape]

You're new to Linux, but you're messing with Arch Linux? Even if you're using UFW to manage your firewall, that's... a rather weird choice for a beginner. I'm guessing you're aware of the "I use Arch btw" meme?

Sorry for that, I don't want to be rude, I just find it very odd.

(EDITED to move the solution upwards, and because now I know WHY you need to allow incoming connections)

TL;DR

Now that you say it, I noticed something weird... if I recall correctly, for me, it only started working after I whitelisted those TCP ports in both directions (into my computer, and from my computer). Why would I need both set of rules, when my rules (and UFW's default rules) explicitly allow all replies to whitelisted connections, is beyond me.

CATT creates an ephemeral web server on your computer when you cast a local file. In order for ChromeCast to access this web server, you need to allow incoming connections on 45000:47000... and the command you gave us should do that.

To be on the safe side, allow outgoing connections FROM those ports too.

The general solution

You don't say how you set up your firewall. I'm guessing you're using the UFW default, deny (incoming), allow (outgoing)?

Your best bet to see what else you need to open in your firewall is to check in your logs which connections are blocked. You can check the Ubuntu documentation for an introduction to UFW, the Arch Linux documentation to see info more in depth and run man ufw to see every single option.

I haven't used UFW in a while now, but glancing at the Arch Linux wiki, I think it logs all blocked connections to the kernel logs by default. You can read those with dmesg.

I'm rambling now

I didn't like this, didn't keep checking what was wrong with this and closed those ports. I don't have use for local casting, currently. (Ignore this, I didn't understand how it worked until I edited the code)

By the way, I can't tell you how you should set up your firewall (it's not my call to make, and I'm no expert), but you might want to learn more about firewalls in general. While I was testing my filters, I specifically set them to accept request to ports 45000-47000 ONLY if they're coming from IP addresses in the range 192.168.1.xxx (in my setup, that's the machines I have at home, and no other machines).

Routers should protect you from random people on the internet randomly reaching those ports on your machine, but if you decided to set firewall in the first place, you might want to watch out for that.