Firewalling

[Gerald Combs]

I would also recommend TCP/IP Illustrated, Volume 1 - The Protocols by W.
Richard Stevens.  The more you know about the inner workings of IP, the
better you will be at administering firewalls.  

Once everything is set up you might want to run a scan using Nessus
(www.nessus.org) and nmap (which someone already mentioned).

On Wed, 17 Oct 2001, Charles Steinkuehler wrote:

> > 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)
> 
> 
> 
> 
>