What do you mean by hanging?  Does it just take a LOOOONG time to boot up?
This would be caused by name lookups typically, or DHCP not finding a server,
or NFS not being able to mount.  In this case, poke a hole for DNS and/or
DHCP (tcpdump is your friend here) in your iptables config file.  For NFS
it's not as easy to just "poke a hole", but there are some brief HOWTO's on
the Net regarding more secure NFS sharing.

Dan W.

On Thu, Aug 03, 2006 at 09:39:05AM -0400, Brent L. Bates wrote:
>      Anyone here have any experience using IP Filter on SL or any other
> Unix/Linux?  We are currently running SL 3.0.5 with kernel 2.4.21-37.EL.XFSsmp
> and IP Filter 4.1.10.  We have problems with IP Filter hanging the system
> during a boot up or if IP Filter is restarted with the system up and running.
>  Once the system is up and running, IP Filter works great.  IP Filter is
> loaded as a module from a startup script.  Any help/suggestions welcome.
>  Thanks.