ipf / pf

[j.l at telus.net]

Hi,

Here's a question that might seem trivial:

What's the relationship between the freebsd ipf and the openbsd pf?  Are they 
the same thing, or are they separately developed branches of a common 
codebase?  Or maybe they are totally different.  I ask this because I was 
looking around for guides for ipf.rules, and some of the openbsd pf examples 
look similar, but some command syntax are different.  The openbsd pf.conf 
example had the ability to define variables of ip addresses, interface names, 
etc, but it doesn't seem to work with ipf.rules.  Is there any way to define 
variables in ipf.rules?

please cc me in your responses cause I'm not subscribed to the list

thanks so much
jonathan