unable to get some client computer name visiting my intranet

Question

Hi,

i am unable to get some client computer name not all visiting my intranet site.any one can help me on this please.

public string GetComputerName(string clientIP)

{

try

{

var hostEntry = Dns.GetHostEntry(clientIP);

return hostEntry.HostName;

}

catch (Exception ex)

{

return string.Empty;

}

}

//call GetComputerName function

string computerName=GetComputerName(HttpContext.Current.Request.UserHostAddress)