Yesterday I changed my ISP to one that allows port forwarding. Today the port forwarding has been enabled by the company and I set it up on the router.
After enabling it, my download and upload speed dropped from peaks of 50 MiB/s and valleys of 4-6 MiB/s to a very stable 2 MiB/s. Nothing else has changed in my qBittorrent configuration. If I close the ports again, the speed goes back to normal. I checked if the ports were open on various websites and all of them show that they are forwarded.
I was looking forward to be able to port forward and connect with every possible peer for years, and today has been a big disappointment in that regard!
Has anyone else seen something like this and if so, can you point me to the right direction to fix the problem?
Edit: Thanks everyone for your time and your help! Still working on it, but it’s heartwarming to be on the receiving end of the goodwill of this community.
Sometimes I love the internet!


The speed test looks fine. Maybe they meter it as you say. Guess I’ll have to contact them so they can explain wtf is happening to my connection.
How did you do the speed test? You need to have an open port on your side and another IP address outside your network.
Ah, I used the speedtest tool of cloudflare, ookla and openspeedtest. You are referring to https://iperf.fr/, right? When I get home I’ll read how to do it properly!
I am a Unix person I just get it from my distro:s package repository. I don’t know if that URL is the correct address.
The steps are (simplified):
This specifically speedtests incoming connections to your IP address. Regular speedtests like fast.com, etc. Test outgoing. With the way TCP/IP works, your ISP can easily differentiate the two.