Rules Actives don't expire

Hi,

I have IP Filter v3.4.29 running in FreeBSD 4.7 and i'm having some
problems. My server die and i discovered that my rules actives in ipfilter
was full. I increased nr_rules_actives for ipfilter, but the problem still
exists. But the problem occurs in a bigger timer. I noticed that with the
time some rules disapper but others no, and with this i again get it full.
Someone know what the problem and how to fix it ?

Sorry for my poor english.
Tanks in advance.

Kleyson Rios.