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?


Just to be sure, did you already test that the port is actually open and forwarded? e.g. with your torrent client running browse to a port test website like https://canyouseeme.org/ , https://www.yougetsignal.com/tools/open-ports/ , etc. put in your torrent client’s incoming port and check if the website can “see” your open port at your torrent client.
And the ISP (or router) itself isn’t doing anything weird to block torrents, right? In your torrent client if you click any working public torrent, click on the Trackers tab, you should see DHT as working along with whatever open trackers are on the public torrent. In other words you won’t see anything like “waiting” something (I forget the exact message you’ll see when DHT is being blocked but it’ll definitely not be working).
EDIT: Also if it’s a new ISP with new router it might have firewall rules set up that are slowing things down, something to check.
Yes, I checked if they were open, and the three sites say they are. I used the ones you sent me, and same results!
Some pwople say that they might be throttling my connection, and I think it is what makes more sense. I’ll have a call with them to see what is happening.
Thanks for pointing out the router firewall, didn’t think about it, but iy is not that either.