Home > Storage > PowerScale (Isilon) > Industry Solutions and Verticals > Media and Entertainment > PowerScale OneFS: macOS Client Performance and User Experience Optimization > Force SMB protocol version
Under certain circumstances, it may be desirable to force macOS to connect through a particular version of SMB. The following edits to /etc/nsmb.conf force a particular SMB version. macOS uses a binary bitmap to specify which version of SMB to use. Add protocol_vers_map= with the appropriate value to force protocol types, as in the following examples.
# Protocol version is specified using binary bitmap
# 1 => 0001 => SMB 1 only
# 2 => 0010 => SMB 2 only
# 3 => 0011 => SMB 1 or 2
# 4 => 0100 => SMB 3 only
# 6 => 0110 => SMB 2 or 3
# To Force SMB 3 only:
protocol_vers_map=4
# To Force SMB 2 or 3 only
protocol_vers_map=6