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Re: Merits of purpose-built (appliance) vs. FreeBSD+ipfw firewalls
- From: Richard A Steenbergen
- Date: Sat Jan 18 20:06:51 2003
On Sat, Jan 18, 2003 at 03:48:03PM -0800, Scott Francis wrote:
> On Sat, Jan 18, 2003 at 12:29:28PM -0500, email@example.com said:
> > As I understand OpenBSD's pf (which may not be complete so feel free to
> > point out if I'm wrong), it isn't actually doing anything to compile
> > normal packet lookups, it just added a non-sequential lookup engine for
> > the truely "stateful" filtering that it does. While this is nice and all,
> > it doesn't replace the functionality of normal rule-based filtering, and
> From pf.conf(5):
> For each packet processed by the packet filter, the filter rules are
> evaluated in sequential order, from first to last. The last matching
> rule decides what action is taken.
> Does this not constitute rule-based filtering? Or am I misunderstanding you?
Yes and no. That would prove my point, if not for the fact that they are
describing the logical processing of a filter ruleset (aka "ipf-style"),
not the implementation of the matching engine.
But still, the stateful filtering and any lookup model it uses does not
negate the need for standard rule-based filtering, and AFAIK pf still
does those comparisons sequentially like any other traditional filter.
Richard A Steenbergen <firstname.lastname@example.org> http://www.e-gerbil.net/ras
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