Firewall

[Miloslav Trmač]

Jesse Keating píše v Po 06. 12. 2010 v 11:00 -0800:
> Right, I always struggle with this.  If you allow services that bind to
> a port once enabled to have the port open, then what good does it do to
> have the port closed?
> 
> I really wonder what real purpose a firewall serves on these machines.
> Once you get past the "ZOMG WE NEED A FIREWALL"....

I can see the following primary reasons to have a firewall:

      * Enforcing a sysadmin-set (system-wide or site-wide) policy.
        
        "No, you will not run any bittorrent client on the company's
        computer".
        
      * A "speed bump" that requires an independent action to prevent
        unintentionally opening up a service.
        
        "You have started $server, and it accepts connections from the
        whole internet.  Here's your chance to think about this again.
        Do you want to open the port?"
        
      * ZOMG WE NEED A FIREWALL
        
        "I can't use this Linux thing, my bank requires me to run an
        antivirus and a firewall."

Are there other reasons?
	Mirek