I'm Rusty Russell; the Linux IP Firewall maintainer and just another working coder who happened to be in the right place at the right time. I wrote ipchains (see How Do I Packet Filter Under Linux? above for due credit to the people who did the actual work), and learnt enough to get packet filtering right this time. I hope.
WatchGuard, an excellent firewall company who sell the really nice plug-in Firebox, offered to pay me to do nothing, so I could spend all my time writing this stuff, and maintaining my previous stuff. I predicted 6 months, and it took 12, but I felt by the end that it had been done Right. Many rewrites, a hard-drive crash, a laptop being stolen, a couple of corrupted filesystems and one broken screen later, here it is.
While I'm here, I want to clear up some people's misconceptions: I am no kernel guru. I know this, because my kernel work has brought me into contact with some of them: David S. Miller, Alexey Kuznetsov, Andi Kleen, Alan Cox. However, they're all busy doing the deep magic, leaving me to wade in the shallow end where it's safe.