[Gllug] Guarddog firewall question

Casper Gasper casper.gasper at gmail.com
Sun Jun 11 01:33:39 UTC 2006

> I am a newbie running Slackware10.2 with KDE desktop.
> I am running the Guarddog firewall application which is a GUI front-end
> for iptables.
> My email provider (nerdshack.com) allows smtp on port 25 & 2525. My ISP
> has port 25 blocked but has 2525 open (after I requested them). I am not
> all that tech savvy when it comes to network & stuffs. I have no clue
> how to configure iptables; but using the Guarddog GUI I enabled smtp
> outgoing, which by default opens port 25. So (using the GUI) I made a
> custom protocol (base on my instincts) which is as follows
> Name: SMPT2
> Type: TCP
> Port: 2525
> and voa-la!! Things are working fine, I am able to send mail fine.
> So before I rush off to my friends to boast & babble about my immense
> talent in configuring firewalls blindly, without having to know anything
> about them :-)..... I would be very grateful if someone could kindly
> confirm if the procedure I followed is OK!! or have I opened some kind
> of a potential security hole??!!
  Have you opened tcp/2525 for outgoing only?  That should be all you
need, as I'm assuming you're not running a smtp mail server.

 Run iptables -vL to see.

> For example there was a choice of the "protocol type" TCP/UDP & under
> UDP there was a choice to make it (so called) "Bidirectional" (I did not
> have a clue as to what all these meant). Should this have been the
> actual protocol type??

  bidirectional I assume means incoming and outgoing traffic.

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