This option specifies the protocol value that smbd 8 will return to a client, informing the client of the largest size that may be returned by a single SMB2 read call. The maximum is 1048576 bytes (1MiB), which is the same as a Windows Server 2008 r2. Please note that the default is 1MiB, but it's limit is based on the smb2 dialect (64KiB for SMB2.0, 1MiB for SMB2.1 with LargeMTU). Large MTU is not supported over NBT (tcp port 139). smb2 max write smb2 max trans 1048576