Finding Subnet to a specified local IP

[CryoEnix]

Hi there, I've been playing around with networking in .NET lately, and I've managed to develop a function to return all of the IP addresses of the local machine - yay! But I digress...

The problem is, I need to find the subnet mask for each of these IP addresses - for example, if I were to pass the IP "192.168.0.1" to a function, I would like it to return the subnet (in this case "255.255.255.0"), or even just a string/boolean telling me if it's a LAN or Internet IP. Anyone?

[PlausiblyDamp]

clicky might be of some help

[CryoEnix]

clicky might be of some help

 

PlausiblyDamp, you're a star, a bloody star!

 

From that code you've given me I've been able to make this function, I hope it helps other people like it helped me:

 

Public Function GetMaskFromIP(ByVal TheIP As String) As String


       Dim mc As New Management.ManagementClass("Win32_NetworkAdapterConfiguration")

       Dim nics As Management.ManagementObjectCollection

       nics = mc.GetInstances()

       Dim nic As Management.ManagementObject

       For Each nic In nics
           If nic("ipEnabled") = True Then
               Dim s As String

               For Each s In nic("IPaddress")
                   If s = TheIP Then Exit For
               Next

               If s <> TheIP Then GoTo TryNextIP

               s = ""

               For Each s In nic("IPSubnet")
                   GetMaskFromIP = s
               Next


           End If
TryNextIP:
       Next

   End Function