Should be pretty straight forward on the needed ports, but just to be sure you get all the right ones, you can:
lsof -i -n |egrep 'smb|nmb'
That'll tell you all of the ports it's listening on.
Dumb, dumb, dumb. It seems I had the firewall activated and was blocking the proper functioning of samba.
I've disabled the firewall for the momment, until I find the time to finetune it configuration.
Hope this may help someone not to make the same mistake!
