Date: Wed, 26 Jul 2006 13:06:14 +0200 From: peter@bgnett.no (Peter N. M. Hansteen) To: freebsd-questions@freebsd.org Subject: Re: pf firewall for a server Message-ID: <87odvczkux.fsf@amidala.datadok.no> In-Reply-To: <200607252030.46540.freebsd@dfwlp.com> (Jonathan Horne's message of "Tue, 25 Jul 2006 20:30:46 -0500") References: <200607252030.46540.freebsd@dfwlp.com>
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Jonathan Horne <freebsd@dfwlp.com> writes:
> ive been googling for a while now this evening, but have
> unsuccesfully found any examples on how to firewall a server. i do
> *not* want to build a router, and unfortunatly, every article i seem
> to find wants to tell me how to build a router!
The same principles apply everywhere - block everyting, allow the
traffic you need. What traffic you need to pass depends on the
services you intend to make accessible. For a host with a single
network interface, you can get away with a handful of lines, ie
localnet="xl0:network"
offered="{ ssh, netbios-ns, netbios-dgm, netbios-ssn, www, https }"
needed="{ ssh, domain, ntp, whois }"
block all
pass proto { tcp, udp } from self to any port $needed keep state
pass proto { tcp, udp } from $localnet to self port $offered keep state
A lot of embellishment on this (untested, may contain nuts) is
possible, and you could probably do worse than spend a few moments
browsing the PF docs or for that matter my rather basic PF tutorial at
http://www.bgnett.no/~peter/pf/ to familiarize yourself with the
system.
--
Peter N. M. Hansteen, member of the first RFC 1149 implementation team
http://www.blug.linux.no/rfc1149/ http://www.datadok.no/ http://www.nuug.no/
"First, we kill all the spammers" The Usenet Bard, "Twice-forwarded tales"
20:11:56 delilah spamd[26905]: 146.151.48.74: disconnected after 36099 seconds
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