every tutorial I could find
Tells me NOTHING about what you have tried. But connecting via a wireless NIC has always been troublesome.
Yes, I have to agree with the first part of the sentence.
Since I wrote the first message, I did a few more tests and I realised that the problem is occuring even if I try to connect GNS3 to my laptop through a loopback interface.
I am missing something but I can not figure what... :)
If you can get it working with a physical NIC first, you may learn enough to trick it into working on your WLAN
Yes, this is an excellent idea but I am currently on holidays and have only access to a wireless network. Will try it in 10 days.
Thank you very much for your help, :)