Apparently, not only is there SMB1, SMB2, and SMB3, but there is also NTLMv1 and NTLMv2. If we need to access older NASes and the like reliably, we may need to create or set this DWORD:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\LmCompatibilityLevel
to 1.