ADD upload user 

sudo useradd -d /home/upload -p $(perl -e'print crypt("upload", "df")') upload 

sudo mkdir /home/upload 

sudo chown upload:upload /home/upload 

Edit /etc/sshh/sshd_config to disable to disable ssh-connection of nand 

Match user nand 

 ForceCommand /bin/false 

  PasswordAuthentication no 

  PubkeyAuthentication no