here we go
Code:'place this code in a separate module 'originally written by Dewayne Basnett in VBA - 1997 'converted to VB .Net - 2007 Option Strict On : Option Explicit On Imports System.Net, System.Text Module IPStuff Const IPbrdcst As Long = 4294967295 '255.255.255.255 FF.FF.FF.FF Dim aIP, aMSK As IPAddress Dim nIP, nMSK, nNET, nHOST, addrs As Long 'numeric equivalents Dim nCIDR, CIDR As Integer Const shBits As Boolean = True 'True = show debug with bits using showBits function Public Function ipRange(ByVal ipAddr As String, _ ByVal ipMask As String) As List(Of String) 'returns a list of all ip addresse on a given network ' 'ipRange("192.168.3.133", "255.255.254.0") '512 hosts - octet crossing ' '255.255.254.0 is /23 'List(Of String) - partial output '192.168.2.0 '192.168.2.1 '192.168.2.2 '... '192.168.2.254 '192.168.2.255 '192.168.3.0 '192.168.3.1 '... '192.168.3.253 '192.168.3.254 '192.168.3.255 'note 'first entry in list is THE network number 'last entry in list is the directed broadcast ' nMSK = IPasNum(ipMask) 'get the Mask as number CIDR = nCIDR 'get CIDR nIP = IPasNum(ipAddr) 'get the IP address as number nNET = IPnetAsNum(nIP, nMSK) 'get THE network number as number addrs = nNET 'addrs = THE network number as number nHOST = IPnumOfHosts(nMSK) 'get the number of hosts If shBits Then Debug.WriteLine("") Debug.WriteLine("IP".PadRight(10, " "c) & showBits(nIP) & " " & ipAddr) Debug.WriteLine("Mask".PadRight(10, " "c) & showBits(nMSK) & " " & ipMask) Debug.WriteLine("Net".PadRight(10, " "c) & showBits(nNET) & " " & NumToIp(nNET)) Debug.WriteLine("Hosts".PadRight(10, " "c) & showBits(nHOST) & " " & nHOST.ToString) Debug.WriteLine("CIDR".PadRight(10, " "c) & CIDR.ToString) 'Stop End If If nIP < 0 OrElse nMSK < 0 OrElse nNET = 0 OrElse nHOST = 0 Then Return New List(Of String) 'error End If ipRange = New List(Of String) For x As Long = 0 To nHOST ipRange.Add(NumToIp(addrs)) 'add host to list addrs += 1 'increment it Next End Function Public Function IPnets(ByVal ipAddr As String, _ ByVal curCIDR As Integer, _ ByVal newCIDR As Integer) As List(Of String) 'returns a list of sub-nets using any IP in the current network, 'the current mask as CIDR and new mask as CIDR. '192.168.3.? /23 to /25 - octet crossing ' 'IPnets("192.168.3.128", 23, 25) ' 'List(Of String) '255.255.255.128 '192.168.2.0 '192.168.2.128 '192.168.3.0 '192.168.3.128 ' Dim curMASK, newMASK, netPlus1 As Long, numOfNets As Integer nIP = IPasNum(ipAddr) 'get the IP address as number If nIP < 0 OrElse curCIDR < 2 OrElse curCIDR > newCIDR OrElse newCIDR > 30 Then Return New List(Of String) 'error End If IPnets = New List(Of String) curMASK = MaskFromCidr(curCIDR) 'convert CIDR's to mask as number newMASK = MaskFromCidr(newCIDR) nHOST = IPnumOfHosts(newMASK) netPlus1 = nHOST + 1 'used to add 1 to the network portion of the ip address nNET = IPnetAsNum(nIP, curMASK) 'get THE network number as number numOfNets = CInt(2 ^ (newCIDR - curCIDR)) 'number of networks IPnets.Add(NumToIp(newMASK)) '<<<<<<<<<<<<<<<<<<<<< first entry in list is the new mask If shBits Then Debug.WriteLine("") Debug.WriteLine("IP".PadRight(10, " "c) & showBits(nIP) & " " & ipAddr) Debug.WriteLine("Network".PadRight(10, " "c) & showBits(nNET) & " " & NumToIp(nNET)) Debug.WriteLine("Cur. Mask".PadRight(10, " "c) & showBits(curMASK) & " " & NumToIp(curMASK)) Debug.WriteLine("New Mask".PadRight(10, " "c) & showBits(newMASK) & " " & NumToIp(newMASK)) Debug.WriteLine("Plus 1".PadRight(10, " "c) & showBits(netPlus1) & " " & NumToIp(netPlus1)) Debug.WriteLine("Num. Nets".PadRight(10, " "c) & numOfNets.ToString) 'Stop End If For x As Integer = 0 To numOfNets - 1 IPnets.Add(NumToIp(nNET)) 'to get last address(broadcast) Dim BrdCst as long = nNET Or nHOST nNET += netPlus1 'add one network number Next End Function Private Function MaskFromCidr(ByVal CIDR As Integer) As Long 'x = 32 - CIDR 'z = (2^x)-1 'return z xor 255.255.255.255 MaskFromCidr = CLng(2 ^ ((32 - CIDR)) - 1) Xor IPbrdcst End Function Private Function IPnumOfHosts(ByVal IPmsk As Long) As Long 'a mask for the host portion '255.255.255.0 XOR 255.255.255.255 = 255 so 0 to 255 is 256 hosts IPnumOfHosts = IPmsk Xor IPbrdcst 'cacluate the number of hosts End Function Private Function IPnetAsNum(ByVal IPnum As Long, ByVal IPmsk As Long) As Long 'extract network from ip address '192.168.2.113 AND 255.255.255.0 = 192.168.2.0 IPnetAsNum = IPnum And IPmsk 'calculate THE network number End Function Private Function IPasNum(ByVal AipAddr As String) As Long 'return -1 on error If Not IPAddress.TryParse(AipAddr, aIP) Then 'convert string to IP Return -1 'error Else IPasNum = IPtoNum(aIP) 'convert IP to number If IPasNum = 0 Then Return -1 'error End If End If End Function Private Function IPtoNum(ByVal theIP As IPAddress) As Long 'convert IP to number Dim IPb() As Byte = theIP.GetAddressBytes 'get the octets Dim theBit As Integer = 31 'work MSb to LSb Dim addr As Long 'accumulator for address nCIDR = 0 For x = 0 To 3 'four octets For y = 7 To 0 Step -1 'with 8 bits each - duh If (IPb(x) And CByte(2 ^ y)) = CByte(2 ^ y) Then 'if the bit is on addr += CLng(2 ^ theBit) 'accumulate nCIDR += 1 'count bits End If theBit -= 1 'decrement bit pos Next Next Return addr End Function Private Function NumToIp(ByVal theIP As Long) As String 'convert number back to IP Dim IPb(3) As Byte '4 octets Dim theBit As Integer = 31 'work MSb to LSb Dim addr As String 'accumulator for address For x = 0 To 3 'four octets For y = 7 To 0 Step -1 '8 bits If (theIP And CLng(2 ^ theBit)) = CLng(2 ^ theBit) Then 'if the bit is on IPb(x) += CByte(2 ^ y) 'accumulate End If theBit -= 1 Next addr &= IPb(x).ToString & "." 'add current octet to string Next Return addr.TrimEnd("."c) End Function Private Function showBits(ByVal aNum As Long) As String Dim strObits As New StringBuilder strObits.Append(Convert.ToString(aNum, 2).PadLeft(32, "0"c)) For ix As Integer = 24 To 0 Step -8 strObits.Insert(ix, " ") Next showBits = strObits.ToString.Trim End Function End Moduleis this worthy of the Code Bank?Code:'get local ip address Dim ipHE As System.Net.IPHostEntry 'declare the structure Dim myIP As String Try ipHE = System.Net.Dns.GetHostEntry("") 'lookup my ip address If ipHE.AddressList.Length > 0 Then myIP = ipHE.AddressList(0).ToString End If Debug.WriteLine(myIP) Catch ex As Exception End Try 'get mask Dim myMask As String For Each networkCard As System.Net.NetworkInformation.NetworkInterface _ In System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces For Each ip As UnicastIPAddressInformation In networkCard.GetIPProperties().UnicastAddresses If ip.IPv4Mask IsNot Nothing AndAlso ip.Address.ToString = myIP Then myMask = ip.IPv4Mask.ToString End If Next Next
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