There’s a nice post about it on the superuser forum here (along with more in-depth posts that you can easily find by searching).
PF = Port Forwarding
w/ = With
wo/ = Without
The TL;DR is that at least one person must have PF enabled in whatever operation you’re performing. So if you’re downloading wo/ PF enabled, then you can only download from seeders w/ PF enabled. If you’re seeding wo/ PF enabled, you can only seed to downloaders/peers w/ PF enabled.
Seeder w/ PF
Seeder wo/ PF
Downloader w/ PF
Yes
Yes
Downloader wo/ PF
Yes
NO
You’ll notice that if you have PF enabled, you’re guaranteed to have all options open, whereas if you don’t, you’re more limited (although in most cases are still able to perform P2P normally)
There’s a nice post about it on the superuser forum here (along with more in-depth posts that you can easily find by searching).
PF = Port Forwarding
w/ = With
wo/ = Without
The TL;DR is that at least one person must have PF enabled in whatever operation you’re performing. So if you’re downloading wo/ PF enabled, then you can only download from seeders w/ PF enabled. If you’re seeding wo/ PF enabled, you can only seed to downloaders/peers w/ PF enabled.
You’ll notice that if you have PF enabled, you’re guaranteed to have all options open, whereas if you don’t, you’re more limited (although in most cases are still able to perform P2P normally)