nanog mailing list archives

Re: Network Segmentation Approaches


From: Andrew Jones <aj () jonesy com au>
Date: Thu, 07 May 2015 09:08:38 +1000

It depends on the software used and implementation.
Many rulesets for pf on BSD start with 'block in on interfaceX' for instance, because it uses a "last match wins" system, unless you use the 'quick' keyword to make rule processing stop if that rule matches.

Andrew

On 07.05.2015 08:30, Scott Weeks wrote:
--- rsk () gsp org wrote:
From: Rich Kulawiec <rsk () gsp org>

The first rule in every firewall is of course
"deny all" and subsequent rulesets permit only
the traffic that is necessary.
------------------------------------


I think you got this backward?  That way all
traffic is blocked, so none is allowed through.
Also, deny by default at the end of the rule
set is not the best thing for every network
that needs a firewall.  Some just want to block
bad stuff they see and allow everything else.
(And some have stated here that they will block
entire countries until their culture changes!)

scott


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