Firewalling

[Charles Steinkuehler]

> I've been handed a couple of bricks and been tossed, fully clothed, into
the
> deep end. Our firewall needs to be analyzed and overhauled and I've been
> volunteered. Can anyone recommend a good book or online intro to
> firewalling? I'm not looking for specific rule sets (although these can be
> helpful) so much as I'm looking for general guidelines. This will strictly
> be for security purposes; we're not looking to limit employee access to
> anything or anywhere.

You absolutely *HAVE* to get O'Reilly's Building Internet Firewalls.
Everything you need from the basics to the advanced, and reference sections
on how to build rules to allow/deny particular protocols.  You don't get
actual rulesets, but you get enough information to build detailed rulesets
regardless of what sort of firewall you're running.

You don't mention what sort of system you're running as a firewall, but if
it's a general purpose PC (running linux, bsd, or whatever), I suggest you
make it single-purpose (firewall/routing duty only), and strip off anything
unnecessary (ie compilers, NFS/port-map, rsh, &c).  I work a lot with tiny
linux images (you can even boot from a single floppy) setup to do just that
(see URL below).

Charles Steinkuehler
http://lrp.steinkuehler.net
http://c0wz.steinkuehler.net (lrp.c0wz.com mirror)