nat w/dynamic ip on external interface

[Ben Bullock <brb_(_at_)_meadvillelibrary_(_dot_)_org>]

I've been reading the Networking FAQ and perusing the misc archives but 
haven't been able to find a definitive answer to a question I know has 
undoubtedly been discussed more than once on this list.  Simply put, if 
I have a LAN with IP address range 192.168.1.0/24 and the external 
interface on the router is ep0, will these rules continue to work when 
the IP address on the external interface (configured with dhclient) 
changes after the system has been running for a few hours/days?

map  ep0  192.168.1.0/24  ->  ep0/32  portmap  tcp/udp 10000:60000
map  ep0  192.168.1.0/24  ->  ep0/32

Thanks for your help.
-Ben