Thank you very much for your help.
I will maybe try doing that, downloading all the deb files needed. Do you
have any idea which ones I would have to download (meaning ones that are not
already installed in Trisquel) ?
I wouldn't think that was the reason, I remember reading an old thread
(before I signed up) where someone (I believe it could have been Ruben, but I
am not positive) said "Trisquel doesn't need a firewall, so having one would
mislead new users".
So, if I can ask (although OT) what has brought you to Trisquel? Or better,
why do you choose a free software only distro?