-=> BO SIMONSEN wrote to KURT WISMER <=-
[snip]
 KW> if you don't connect to the internet then you have no need for one,
 KW> otherwise you do...

 BS> I connect to the Internet yes.. My server is online 24/7, but still
 BS> there is no reason for a firewall because the only ports which is
 BS> opened is needed. I see now reason for filtering outbound traffic.

because you have perfect knowledge of everthing accepting incoming or
making outgoing connections and can guarantee that that set of things
never changes?

you use a firewall to block incoming connections because the possibility
exists that you might make an error in judgement about some attachment
or some program you downloaded or your browser is exploited in such a
way that an unwanted server app gets installed on your computer without
your knowledge...

you use a firewall to block outgoing connections because those same
possibilities exist for malware that calls home or likes to do other
things (like spread) online...

a firewall is like a safety net... better to have it and not need it
than to need it and not have it...

 KW> it used to be that people would talk about the
 KW> myth of the firewall (the myth being that firewalls were necessary) -
 KW> nobody mentions the myth of the firewall anymore...

 BS> Firewalls are nessersary if you can't close all ports which could make
 BS> damage on the system. A firewall in my terms is a ip filter, not all
 BS> those fancy windows crap, like Zonealarm. ;-)

closing ports is all well and good... the only thing is that those ports
aren't really 'closed' - what you're really doing is stopping applications
from listening on those ports... other applications could start
listening on those or other ports at some point *after* you go around
closing ports... then what?

a firewall isn't just a preventative measure, it's a detective measure
as well... if you don't have anything monitoring connection requests you
won't know if something new and unwanted is trying to make connections...
 
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