Compare IP address to a range

I would like to validate users to my site my testing if their IP address is within a given range. How should I go about this? The IP address is given in the dotted format such as 203.51.115.650.

I have experimented with using strings to compare values and this seems to work, but I'm sure there must be a more robust way to test. For example I used the below code:



Dim ipadd As String = Request.UserHostAddress


Dim myIpUpper As String = 'Get upper IP value from Database


Dim myIpLower As String = 'Get lower IP value from Database


If ipadd >= myIpLower And ipadd <= myIpUpper Then


Label1.Text = "registered ok "


Else


Label1.Text = "NOT registered"


End If





Does the .NET framework provide a method to test whether an IP address is within a range?