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!


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.
Man, if this is the simplified version, I’m totally fucked. I understand every word, but the order in which they are stringed together confuses me.
I’m waiting for a call of my ISP’s IT service to see what’s what. If they can’t (or won’t) fix my issue, I’ll bite the bullet and I’m gonna buy a subscription to a VPN.
Thank you for the detailed explanation!
Its identical ish to what you’d do if you host a website. You can also do that and just try downloading a large file from it (still while outside your network)