how many IPFW rules?

[eBoundHost: Artur]

Hello FreeBSD people!

I have a smtp server under attack by what seems like a large botnet.  My 
inetd is choking under the load and not allowing real mail through.  I've 
successfully used tshark to find the offenders and put them into ipfw 
firewall for port 25.

So here is my question, I'm currently blocking 55,529 ip addresses and the 
server seems pretty snappy, with no noticible load or lag.  How many more 
rulesets will I be able to handle before things start getting fuzzy?

Best Regards,

Artur
eBoundHost.com
http://www.eboundhost.com