defaults write com.apple.desktopservices DSDontWriteNetworkStores -bool TRUE
See also HT208209 at Apple.
sudo defaults write /Library/Preferences/SystemConfiguration/com.apple.smb.server SigningRequired -bool FALSE
Client packet signing disabling is configured by linking nsmb.conf to /etc/nsmb.conf
.
See also HT205926 at Apple and article at Promise.