On 18 Oct 2018 18:13:13 GMT, Frank Slootweg wrote:

I re-checked my notes and at the time, I looked at:

'SMB cifs samba file server'
https://play.google.com/store/apps/details?id=com.imperioustech.www.sambaserver
"Uses Standard port 445 for rooted devices and automatically
selects a suitable port for non-rooted devices."

I didn't proceed with this, for the very reason you are now
investigating, the need to map port 445 to a port number above 1024.

Perhaps 'SMB cifs samba file server' is a candidate for you to
investigate.

Hi Frank,
Thanks for your helpful advice.

Given that we seek a general solution that works for most people,
you're correct that the way to approach solving this age-old problem
is in two parts, where we (first) find an Android SMB server that can work
on ports higher than 1024 on Nougat and above without being root, and then
we (second) map Windows SMB TCP requests to be on the same higher-than-1024
port (e.g., 7777).

Unfortunately, that com.imperioustech.www.sambaserver APK isn't on Google
Play, or on F-Droid, so, while both problems are formidable, we're stuck
with no resolution until we can find an SMB server for Android that can
change the port without being root.

Once we get an SMB server working, we can map Windows TCP port 445-7777.
So we're all stuck, until we can find an SMB server that works sans root.