using a hostname instead of an ip address

[Michael Grant]

I'm running ipf: IP Filter: v3.4.31 (336)
Kernel: IP Filter: v3.4.31
on Freebsd 4.10

I need to open a hole for someone with a dynanic ip address.  They
have a hostname via dyndns.org.  If I put the hostname in my ipf.conf
file, when his address changes, will ipf use the new address
automatically?  Or do I need to reload my firewall rules via crontab?

Michael Grant