In an article published on ZDNet in June 2011, entitled "Five Chromebook concerns for businesses", Steven J. Vaughan-Nichols faulted the devices for lack of virtual private network capability, not supporting some Wi-Fi security methods, in particular Wi-Fi Protected Access II (WPA2) Enterprise with Extensible Authentication Protocol-Transport Layer Security (EAP-TLS) or Cisco's Lightweight Extensible Authentication Protocol (LEAP). He also noted that its file manager does not work, the need to use the undocumented crosh shell to accomplish basic tasks such as setting up a secure shell (SSH) network connection as well as serious deficiencies in documentation.[60]