Documentation on SPFs

[Crispin Cowan <crispin () cse ogi edu>]

I'm looking for documentation on the specification notations for
Stateful Packet Filters (SPFs) or whatever it is that the vendor in
question calls it.  Web surfinng, I've been able to locate marketing
info that tells me that vendors such as Cisco (
http://www-au.cisco.com/warp/public/778/security/firewall/firew_wp.htm )
and Checkpoint (
http://www.checkpoint.com/products/technology/page3.html ) HAVE stateful
inspection engines, and how much better they are than proxies and packet
filters, but I can't find any documents that tell me how the admin can
specify the stateful filtering configuration of what is and is not
allowed.  I'm particularly interested in comparing the expressiveness of
these specifcation notations.

Thanks,
    Crispin
-----
 Crispin Cowan, Research Assistant Professor of Computer Science, OGI
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