IMHO - it is a shame that .Address is an ObsoleteAttribute("This property has been deprecated...

DimtestIPAsIPAddress=IPAddress.Parse("192.168.1.1")
DimtestMaskAsIPAddress=IPAddress.Parse("255.255.255.255")
Dimtestadd1AsIPAddress=IPAddress.Parse("0.0.0.1")
testMask.Address=testIP.AddressAndtestMask.Address
Debug.WriteLine(testMask.ToString)
testIP.Address=testMask.Address+testadd1.Address
Debug.WriteLine(testIP.ToString)

when working with Mask's or ranges of IP's you can't beat it.

This property should not go away, unless there is an equally easy way to work with address ranges and mask's.