[1]https://mullvad.net/en/blog/2023/5/29/removing-the-support-for-forwarded-ports/
- As of today (29 June 2023), Port forwarding is not offered for new customers as part of the Pro plan. Further, existing IVPN Pro customers cannot reserve new ports. Existing reservations will stay in place, and can be disabled by manual action.
- We are disabling all reserved ports and completely remove this feature from our service on 30 September 2023.
[1]https://www.ivpn.net/blog/gradual-removal-of-port-forwarding
[2]https://safereddit.com/r/IVPN/comments/13uun18/comment/jm6fo23/
For those who are lost in vain and don't understand what port forwarding is, calm down, nothing changes for you if you don't set up Plex Media Server, haven't been seeding torrents or if you don't set up virtual private network at your home to access it from a remote location.
Port forwarding bypasses the NAT firewall and allows external sources to access your device easily. It improves your internet speed and increases download time but it comes with the cost and the price is security because open ports, if not constantly occupied, make it easier for hackers to successfully attack you.
Most of the time, port forwarding is very useful in P2P file sharing. To directly answer your question, when you seed torrents, people who want to download from you have to access your torrent files through an open port on your network. As Mullvad and IVPN say, they removed port forwarding because some users were using it for hosting and sharing of illegal materials.
This is just an excuse to remove port forwarding features, an excuse similar to why you are asked to upload KYC documents on centralized exchanges.
If you are more interested in Port Forwarding, you can check some good articles:
Port forwarding: What it is and how to set it up - This article is focused on why you shouldn't use port forwarding.
VPN Port Forwarding - Neutral article.
What is NAT Firewall.
Supercharge peer-to-peer speeds with port forwarding.