[Samba] system error 58 when guest connects from Win10

[Klaus Hartnegg]

> Am 04.05.2017 um 17:49 schrieb Klaus Hartnegg:
> I cannot connect as guest from Win10 to Samba anymore,
> since I removed "server max protocol = NT1"

Finally found the answer:
win10-1709 disables guest access to shares using SMB2.

You can re-enable insecure guest logons via GPO:
Computer configuration\administrative templates\network\Lanman Workstation

However Microsoft discourages this because security:
"Guest logons do not support standard security features such as signing and encryption. Therefore, guest logons are vulnerable to man-in-the-middle attacks that can expose sensitive data on the network. Windows disables "insecure" (nonsecure) guest logons by default. Microsoft recommends that you do not enable insecure guest logons."
https://support.microsoft.com/help/4046019

Additionally I found that if samba runs as AD-DC, then guest logon appears to work again. Presumably because in this case the client is also authenticated to the server with its machine account.