Thanks. I have installed Gtk-Gnutella 1.1.0 and as far I can see, it has connected in a second or less!!! It shows activity and it shows items when I search for keywords. I did not open any port in the router. There is a connected gray cable on the left bottom, and a violet plug icon on its right and the "http://gtk-gnutella.sourceforge.net/" URL shown on the its right side. If I place the mouse pointer over the plug icon, it says: Port mapping configured though UPnP. I understand that it means that no port mapping is required in the router. Right?

I have also installed WireShare 5.6.4 as well as WireShare 5.6.3.1b, yet the same of WireShare 5.6.4.1 issues arise. I could not find older versions to install and test.

In my latest tests I used Universal Plug 'n' Play, so no port forwarding in the router is required as far as I understand. As indicated above, that is default WireShare installation and the way it is configured in the iMac where WireShare works OK.

Previously I did tests mapping the ports on the router using the private IP of the Mac mini (not the iMac). I have experience with that, since have done it also in the past with LimeWire when it worked and with the numerous testings when it stopped working, as well as after installing WireShare some time ago.