[techtalk] Gnome Panel items and TCP ports

[Rick Scott]

> A port scan conducted during my login session show that different
> applets on the control panel use different ports on the system.  I
> have blocked these ports using ipchains. The bigger problem is, on a
> different login session, the applets were using different ports. Is
> this normal behaviour of the GNOME applets?
 
Are the applets listening, or "dialing out"?
I'm not very familiar with Gnome, but the standard behavior of most
internet applications that don't need to listen on a certain 
port is that they'll pick some random non-priviledged port 
(port # > 1024) to do their connections.  

That doesn't sound very clear.  Say, on your machine, you're 
webserver.  Using a browser on the same machine, you request a 
few pages.  The connections will go something like

       (Web browser)          (Web server)
machine.domain.net:1033  ->  machine.domain.net:80
machine.domain.net:1034  ->  machine.domain.net:80
machine.domain.net:1035  ->  machine.domain.net:80

Of course, if the applets are supposed to be *listening* on a
certain port, I'm right out to lunch.  I don't know about the
Gnome applets, but sysadmins at a place I used to work at told
me that ICQ, in particular, was exceedingly good at finding out
what ports were open in your firewall and using them.


Rick
-- 
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The quest for truth died with the birth of the net. 
Now we have all the truth we could ever want. 
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