Controlling the Adaptive Firewall with `afctl`

Question

For those of you that don't know, afctl controls (is?) Leopard Server's Adaptive Firewall. Its a really cool program, you give it an IP address, and a time-to-live in minutes, and that ip instantly gets firewalled for about that many minutes.
Here is the man page for the program:
http://developer.apple.com/documentation/Darwin/Reference/ManPages/man8/afctl.8. html
And here is the man page for it's config file:
http://developer.apple.com/documentation/Darwin/Reference/ManPages/man5/af.plist .5.html
At first it seems like the perfect program. But I'm having big problems with it, all regarding rule numbers.
afctl's first firewall rule is number 1700. Its next rule is 1705. And so on and so on. Now my rules come from a script I have running on my server, that automatically 'detects' abusers and blocks them. Rules last for 1 hour. So after the first hour of running, rule 1700 will expire, then 1705 and so on. New rules that are constantly getting generated, are up to maybe lets just say 1840.
So even though rules only last an hour, the rule numbers keep going up and up and up. This becomes a big problem because once the rules get to 12300, the overlap and then pass existing rules in ipfw. Once they surpass this, incoming packets are matched and accepted before they get to their block rule (generated by afctl). So every second or so, another and another and another firewall rule gets added to block that same IP. But the rules are so high they don't work. Multiply this by 30 or 40 IPs at a time and you can see how once my afctl rules get to 12300, total chaos ensues.
If I totally disable my script for two hours, and let all my afctl rules expire. Then I can re-enable the script and it will start generating rules again at 1700. But this can be a problem, some times I'm getting more traffic than I can handle during those two hours. After about 250 requests per second, things start to get sketchy.
I need a way to manage these rule numbers without having to turn off the script that makes these rules.
One thing that confuses me is the 'default_set' setting in the af.plist file. I'm not sure what this means, but does this somehow let me put my afctl rules into their own 'group'? The default setting for 'default_set' in my plist file is 17. That means nothing to me though. Reading the ipfw man page, it refers to it's whole configuration as it's 'ruleset'. So I'm not sure what this setting is, or if it can help me.
As it stands now, I have to 'reset' my rules (by way of disabling my script and letting all afctl created rules expire) about every other day. If I could have afctl rules increment by 1 instead of 5, that would give me about 10 days. Still a bandaid, but a better bandaid. If there was a way to make afctl choose rules that are the lowest available rule number greater than 1699, so as rules expired, their numbers would be recycled. That would also work. Although i'd feel better if my dymanic rules also had a greater range to life in, than 1700-12300. But I'd have to be under one **** of an attack for that not to be enough.

Answer 1

Well I found a solution, but it's not great. I run the following commands daily (nightly).
sudo rm /var/db/af/blacklist;
sudo ipfw delete set 17;
sudo /usr/libexec/afctl;
This deletes any memory afctl has of it's rules. Then it manually deletes all the rules it's made. Then it recreates it's database file.
This will make your rules start over every night so you won't get 'rule number overflow' headaches.
OF COURSE the whole point of afctl is auto-expiring firewall rules. So if you're going to do this, I might as well have my server firewall addresses directly to ipfw instead of bothering with afctl. I'm going to leave it using afctl now only because its already set up and running. At least I can be away from my server now without having a rule number overflow which for several different reasons brings my server to it's knees.