The CD Netinst image at https://cdimage.debian.org/cdimage/ports/current-hurd-i386/iso-cd/debian-hurd-2019-i386-NETINST-1.iso always fails to connect to the internet for me. It errors out once it has to download information on the mirrors, no matter what mirror I set it to. The error is something like "failed to retrieve file".
I think my problem with the preinstalled images was with apt, which I was never able to configure properly. Looking back on it now, it was probably a misconfiguration on my part. Because I discovered the DVD ISO, which "Just Works" for me, I stopped looking into these problems.
