IIS Websites and Browsing Stop When qBittorrent is Running on Windows Server 2019

[aosssy]

I'm experiencing a curious issue on my Windows Server 2019 with IIS and qBittorrent. I have two websites hosted on IIS and use qBittorrent to share files. Everything works perfectly until I start torrenting. As soon as qBittorrent begins downloading, any attempt to browse the internet using any web browser on the server fails. However, other internet-dependent applications like Anydesk and RDP remain unaffected, and the torrent client itself continues downloading without issue.

Here's what I've observed and investigated:

• Port conflict: I checked if qBittorrent is using port 80 (used by HTTP), but it's not.

• Website accessibility: Interestingly, when torrenting, my IIS websites become inaccessible from other devices over the internet. However, I can still access them directly through the http://localhost on the server itself.

• Remote Port 80 Check: I've also attempted to remotely check port 80 using https://portchecker.co/ while the issue is occurring, and it indicates that port 80 is closed on the server. This further supports the notion of a conflict or disruption affecting IIS's ability to serve web traffic.

I'm seeking advice from the community on potential causes and troubleshooting steps to resolve this issue. Any insights or suggestions would be greatly appreciated!

[Peter]

- Check advanced settings, you can bind qBittorrent to the public network interface
- Check if you have qBittorrent WebUI enabled, it may take up a port you need
- Check ports used:
-- in command line: netstat -abn
-- with GUI: https://learn.microsoft.com/en-us/sysin ... ds/tcpview

- You could put qBittorrent into a Hyper-V machine and torrent that way, I don't know, just an idea.
- I am not sure what you use IIS for, but unless you need to host ASP stuff, you can just install a Debian/Ubuntu or whatever into a VM and use that to serve your web traffic. You can set up port forward even with the "Default Switch" (NAT).

[aosssy]

My webui works on 127.0.0.1:10005.
Also disabling it didn't fix the issue.