mount cifs windows7 mount error(13): Permission denied报错

之前使用cifs挂载windows2008使用以下语句是没有问题的:
mount -t cifs -o username=dearda,password=123456 //192.168.33.189/soft /mnt/soft

但目标机器为windows7时,执行上述语句报错(权限没有问题):
mount error(13): Permission denied
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

解决方案如下,语句增加一个参数sec=ntlm:
mount -t cifs -o username=dearda,password=123456,sec=ntlm //192.168.33.189/soft /mnt/soft