There have been internal discussions about removing PF from NetBSD. Currently, NetBSD’s PF is 11 years old, has received no maintenance, and has accumulated bugs and vulnerabilities that were fixed upstream but not in NetBSD.
Those justifications seem reasonable. I did like that I could carry my PF rules across from other BSDs, which lowered the barrier to entry for the few NetBSD VMs I run. But I should learn NPF.
Importing recent versions of PF in scalable/performant kernels is a huge work because of PF’s legacy design, and there have been reports that FreeBSD is also considering dropping PF.
This is news to me, though perhaps it shouldn’t be. I used to use PF everywhere on FreeBSD until AsiaBSDCon 2018 when I overheard a conversation from some FreeBSD veterans discussing how much more traffic could be pushed through IPFW. I prefer PF’s syntax, and haven’t ever hit any bottlenecks using it, but perhaps I should revisit IPFW.
The biggest barrier to entry for me is jails. Most documentation online discusses how to configure networking into jails using PF, and I’ve done it this way for so long it’s basically rote. IPFW by comparison almost needs something like Firehol, though its syntax is still far better than nasty Linux IPtables.