Getting Remote Computer Name

Hi,
I have hosted my site on IIS 5.1 and I want to retrieve the computer name which is accessing my webpage.I'm currently using the following code but sometimes it returns me with a number instead of the computer's name.
Dim computer_name As String() = System.Net.Dns.GetHostEntry(Request.ServerVariables("remote_addr")).HostName.Split(New [Char]() {"."c}) Dim ecn As [String] = System.Environment.MachineName

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