nat holding onto entries

I use ipnat on my dynamic dialup ip connection. I basically leave the
connection up all the time but from time to time my isp bumps me off
and it dials right back up.

I have noticed that my connections which are still up when the line
bounced keep the old ip address in the nat table. I have to manually
execute 'ipnat -F' to flush the entries. Is this a known problem?

I'm using ipfilter 3.4.31.

Michael Grant