Sepherosa Ziehau is switching DragonFly from IPFW1 to IPFW2, which has the same rule syntax. Gergo Szakal helpfully pointed out that the differences between the two versions are listed in the IPFW man page under “IPFW2 ENHANCEMENTS”.
A running description of activity related to DragonFly BSD.
Note that I am not (and have never been) an active IPFW user. I just tried it like 3 or 4 years ago in FreeBSD and it worked. I don’t recall if it was v2 or v1, because after a few days I switched to pf (bear in mind that I did not know any Unix firewalling and knew only a tiny TCP/IP).
Well, PF is IMHO the best known firewall, but IPFW2 has a more easy configuration and administration, it is a good choice too.
Is IPFW2 easier than PF? I don’t think so.