Things are very quiet this week; I’ve had nothing to post for some days – DragonFly or even for other BSDs. The end of the year has most people distracted, I think. This makes it a good time to bring up something that’s been bothering me: the state of software firewalls in BSD. The pf utility is a BSD advantage; I’ve heard people say “I used iptables on Linux and pf is a much better alternative.” I know that’s anecdotal, but there it is. Here’s the question, and the reason I’m writing this: which pf?

DragonFly has a version of pf equivalent to what was shipped in OpenBSD 4.4. FreeBSD has a version equivalent, I think, to OpenBSD 3.8 4.5’s pf, and it has been further modified. NetBSD has a similar, older pf, but there’s people working on a NetBSD-specific version called npf, which isn’t yet ready. And of course, OpenBSD has its version of pf. If you feel good about these different alternatives, you call it divergence. If you don’t feel good about it, you call it fragmentation.

Compare this to OpenSSH – it works the same on each platform. There’s no confusion on how to configure it, or interoperability problems. It would be wonderful to have the equivalent for pf, where other BSD platforms would import a portable version. This software firewall is a strength, and it’s much easier to tout it when there’s only one.

I doubt there’s a way to bring it all back to one source tree. There’s a lot vested in the different forks out there. You know what would take a lot less effort: a compatibility test suite. Agreeing on a common syntax and set of functions would make life easier for every end user. It would incidentally make vendors a lot happier, too. Even if a user or vendor wasn’t hoping to move between BSD flavors, a test suite would still guarantee a certain known level of functionality for any BSD release.

How likely is this? I don’t know. But I want to bring up the notion before it gets missed. Now is a good time, with each pf version still being relatively close to one another.

Update/note: Henning Brauer is willing to help.