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On Tuesday 27 February 2007 03:21, Grant wrote: |
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> > > > Anyway, a closed port remains closed whether a firewall is running, |
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> > > > or not. |
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> > > |
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> > > I thought the firewall specified which ports to open/close. |
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> > |
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> > Not quite, but we might be running into terminology here. |
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> > |
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> > The app that is listening a port opens the port. This has nothing to do |
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> > with the firewall. The firewall is simply an extra level of checks |
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> > applied before the packet is allowed thorugh the firewall to be |
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> > received by the kernel, in the same way that a bouncer allows or |
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> > disallows the public to enter a club. If the bouncer is off sick, the |
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> > public gets to walk through the door up to reception, assuming the club |
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> > is open for business. |
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> > |
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> > What Mick was referring to is that if a service is running, it's still |
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> > going to listen on it's port whether iptables is running or not. So, in |
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> > the absense of iptables (i.e. your bouncer is off sick), you hopefully |
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> > have a decent password strategy in use by whatever is actually |
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> > listening on the box. |
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> |
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> So as far as incoming connections are concerned, if there are no |
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> listening applications, there is no need for a firewall? |
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As I understand it, no. However, a firewall is there to offer additional |
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functionality and protection by logging packets, filtering the amount of |
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incoming packets, proactively blocking some of these from coming in, etc. |
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After all you would be less inclined to allow a machine which has been |
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scanning your server ports for the last 10 minutes to try to authenticate on |
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a legitimate service port, right? |
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http://www.gentoo.org/doc/en/articles/dynamic-iptables-firewalls.xml |
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-- |
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Regards, |
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Mick |
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