security of a new installation / steps to take

Paul Schmehl pauls at
Wed Feb 20 18:37:35 UTC 2008

--On Wednesday, February 20, 2008 17:22:02 +0000 Matthew Seaman 
<m.seaman at> wrote:

> Hash: SHA256
> Zbigniew Szalbot wrote:
>> So far I have had FreeBSD systems only in office so I used my hardware
>> firewall (Dlink DFL 700) to block access to services on ports 22, etc.
>> Now, at the ISP I won't be able to do this so I will need to be a lot
>> more careful about security issues. I am planning to make a list of
>> steps I need to take to configure the OS to my liking and install
>> applications I need. However, I would really, really love to have some
>> advice from you re the basic steps.
> The important mantra to remember when securing a machine that is exposed
> to the internet is:
>     What does not listen on the network cannot be used to compromise you.
> In practice, this means run sockstat and look for all the processes
> that are listening for connections on your external network interfaces.
> If you don't need it, then don't run it.

What an outstanding answer.  Matthew has covered all the correct bases.  I can 
only add one further suggestion.  Consider using /etc/hosts.allow to protect 
daemons that must listen on ports to restrict access even further.

Paul Schmehl (pauls at
Senior Information Security Analyst
The University of Texas at Dallas

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