[seq] Can't ssh to a Cygwin machine in the Windows domain -- seteuid

[Nicola Mingotti <nmingotti@gmail.com>]

This is a sequel to the message:
"Can't ssh to a Cygwin machine in the Windows domain -- seteuid"
Sent 20 Dec 2020 to the mailing list. I was not subscribed, I found no
other way to replay the message than to subscribe and make a 'sequel'. 
sorry for this.

For quick reference, the original message is here:
https://cygwin.com/pipermail/cygwin/2020-December/247089.html


*] To Kevin
I tried :
$> ssh WINDM+nicola
But that does not solve, in this case the user is not recognized.
------- sshd output ------------
...
debug3: mm_answer_authpassword: sending result 0
debug3: mm_request_send entering: type 13
Failed password for invalid user WINDOM+nicola from 172.16.3.50 port 
54596 ssh2
debug3: mm_auth_password: user not authenticated [preauth]
debug3: user_specific_delay: user specific delay 0.000ms [preauth]
debug3: ensure_minimum_time_since: elapsed 53.119ms, delaying 17.592ms 
(requested 8.839ms) [preauth]
debug3: userauth_finish: failure partial=0 next 
methods="publickey,password,keyboard-interactive" [preauth]
debug3: send packet: type 51 [preauth]
------------------------------------


Supplementary information:

*] Forcing user/password authentication does not work
$> ssh -o PreferredAuthentications=password -o PubkeyAuthentication=no 
nicola@domus
---- sshd output ----
debug1: session_input_channel_req: session 0 req pty-req
debug1: Allocating pty.
debug1: session_pty_req: session 0 alloc /dev/pty2
debug1: Ignoring unsupported tty mode opcode 52 (0x34)
debug1: Ignoring unsupported tty mode opcode 62 (0x3e)
debug1: pty_setowner: no tty group
chown(/dev/pty2, 1049679, 1049089) failed: Permission denied
debug1: do_cleanup
debug1: session_pty_cleanup2: session 0 release /dev/pty2
--------------------------------------


*] The only thing that works is logging in as the 'cyg_server' user.
But that defies the whole purpose to define such user.
$> ssh cyg_server@domus


bye
Nicola