SMB_IP=""
SMB_SHARE=""  # eg. /Share
MNT_POINT=""
USER=""
PASSWORD=""  # escape special characters eg. "P@\$\$W0rd\!"
LOCAL_UID="0"
LOCAL_GID="0"

# install
apt-get install cifs-utils

# mount freenas samba share on debian 9
mount -t cifs //$SMB_IP$SMB_SHARE $MNT_POINT -o user=$USER,pass=$PASSWORD,vers=3.0,sec=ntlm,file_mode=0775,dir_mode=0775,gid=$LOCAL_GID,uid=$LOCAL_UID

# unmount share
umount /mnt/freenas

# as fstab entry
# *NOTE* $PASSWORD should not be escaped in fstab
//$SMB_IP$SMB_SHARE $MNT_POINT cifs username=$USER,password=$PASSWORD,vers=3.0,sec=ntlm,file_mode=0775,dir_mode=0775,gid=$LOCAL_GID,uid=$LOCAL_UID 0 0