Retrieving all Server Environment variable values

How to retrieve all Server Environment variables at one go. Just place
this code in .aspx page run it.

<div>
<table width="70%" align="center">
<tr bgcolor="#FF9900">
<td width="25%" align="center">
ServerVariable:
</td>
<td width="75%">
Value
</td>
</tr>
<% foreach(string Item in Request.ServerVariables){ %>
<tr>
<td width="25%">
<%= Item %>
</td>
<td width="75%">
<%=Request.ServerVariables[Item]%>
</td>
</tr>
<% } %>
</table>
</div>