我想生成200,000个随机IP地址而不重复相同的IP地址 例如：
（1-254）。（1-254）。（1-254）.1-254）
在vb.net中 我的代码是：
While c < 200001
IP = random.Next(1, 254).ToString + "." + random.Next(1, 254).ToString + "." + random.Next(1, 254).ToString + "." + random.Next(1, 254).ToString
On Error Resume Next
IPHost = Dns.GetHostEntry(IP.ToString)
domain = IPHost.HostName.ToString()
objWriter.Write(IP)
objWriter.Write(" ")
objWriter.WriteLine(domain)
TextBox1.Text = IP
Application.DoEvents()
End While
objWriter.Close()
MsgBox("DONE")
问候
答案 0 :(得分：3)
踩过保留IP块等问题，您可以简单地将生成的IP写入Collection，然后调用集合的Contains()方法来检查集合中是否存在生成的IP
正如@Heinzi指出的那样，HashSet也是一个选择 - 也许是一个更好的选择，因为你正在写200,000个条目。
答案 1 :(得分：2)
由于IP4地址由4个字节组成，因此您只需使用大小为4的数组Random.NextBytes即可创建一个。
要防止创建重复的地址，只需使用HashSet和while循环。
要过滤掉保留地址，您只需使用this answer中使用的代码（一些保留地址很容易检查，例如多播地址都以1110开头，但不需要重新发明轮子）。我将它转换为VB.Net下面的
所以你的代码看起来像这样：
Dim r = New Random()
Dim addresses = New HashSet(Of String)()
While addresses.Count < 200000
Dim buffer As Byte() = New Byte(3) {}
r.NextBytes(buffer)
Dim address = String.Join(".", buffer)
If Not IsNonRoutableIpAddress(address) Then
addresses.Add(address)
End If
End While
以及IsNonRouteableIpAddress的转换代码：
Public Shared Function IsNonRoutableIpAddress(ipAddress__1 As String) As Boolean
'Reference: http://en.wikipedia.org/wiki/Reserved_IP_addresses
'if the ip address string is empty or null string, we consider it to be non-routable
If [String].IsNullOrEmpty(ipAddress__1) Then
Return True
End If
'if we cannot parse the Ipaddress, then we consider it non-routable
Dim tempIpAddress As IPAddress = Nothing
If Not IPAddress.TryParse(ipAddress__1, tempIpAddress) Then
Return True
End If
Dim ipAddressBytes As Byte() = tempIpAddress.GetAddressBytes()
'if ipAddress is IPv4
If tempIpAddress.AddressFamily = System.Net.Sockets.AddressFamily.InterNetwork Then
If IsIpAddressInRange(ipAddressBytes, "10.0.0.0/8") Then
'Class A Private network check
Return True
ElseIf IsIpAddressInRange(ipAddressBytes, "172.16.0.0/12") Then
'Class B private network check
Return True
ElseIf IsIpAddressInRange(ipAddressBytes, "192.168.0.0/16") Then
'Class C private network check
Return True
ElseIf IsIpAddressInRange(ipAddressBytes, "127.0.0.0/8") Then
'Loopback
Return True
ElseIf IsIpAddressInRange(ipAddressBytes, "0.0.0.0/8") Then
'reserved for broadcast messages
Return True
End If
'its routable if its ipv4 and meets none of the criteria
Return False
'if ipAddress is IPv6
ElseIf tempIpAddress.AddressFamily = System.Net.Sockets.AddressFamily.InterNetworkV6 Then
'incomplete
If IsIpAddressInRange(ipAddressBytes, "::/128") Then
'Unspecified address
Return True
ElseIf IsIpAddressInRange(ipAddressBytes, "::1/128") Then
'lookback address for localhost
Return True
ElseIf IsIpAddressInRange(ipAddressBytes, "2001:db8::/32") Then
'Addresses used in documentation
Return True
End If
Return False
Else
'we default to non-routable if its not Ipv4 or Ipv6
Return True
End If
End Function
''' <summary>
'''
''' </summary>
''' <param name="ipAddressBytes"></param>
''' <param name="reservedIpAddress"></param>
''' <returns></returns>
Private Shared Function IsIpAddressInRange(ipAddressBytes As Byte(), reservedIpAddress As String) As Boolean
If [String].IsNullOrEmpty(reservedIpAddress) Then
Return False
End If
If ipAddressBytes Is Nothing Then
Return False
End If
'Split the reserved ip address into a bitmask and ip address
Dim ipAddressSplit As String() = reservedIpAddress.Split(New Char() {"/"C}, StringSplitOptions.RemoveEmptyEntries)
If ipAddressSplit.Length <> 2 Then
Return False
End If
Dim ipAddressRange As String = ipAddressSplit(0)
Dim ipAddress__1 As IPAddress = Nothing
If Not IPAddress.TryParse(ipAddressRange, ipAddress__1) Then
Return False
End If
' Convert the IP address to bytes.
Dim ipBytes As Byte() = ipAddress__1.GetAddressBytes()
'parse the bits
Dim bits As Integer = 0
If Not Integer.TryParse(ipAddressSplit(1), bits) Then
bits = 0
End If
' BitConverter gives bytes in opposite order to GetAddressBytes().
Dim maskBytes As Byte() = Nothing
If ipAddress__1.AddressFamily = AddressFamily.InterNetwork Then
Dim mask As UInteger = Not (UInteger.MaxValue >> bits)
maskBytes = BitConverter.GetBytes(mask).Reverse().ToArray()
ElseIf ipAddress__1.AddressFamily = AddressFamily.InterNetworkV6 Then
'128 places
Dim bitArray As New BitArray(128, False)
'shift <bits> times to the right
ShiftRight(bitArray, bits, True)
'turn into byte array
maskBytes = ConvertToByteArray(bitArray).Reverse().ToArray()
End If
Dim result As Boolean = True
'Calculate
For i As Integer = 0 To ipBytes.Length - 1
result = result And CByte(ipAddressBytes(i) And maskBytes(i)) = ipBytes(i)
Next
Return result
End Function
''' <summary>
'''
''' </summary>
''' <param name="bitArray"></param>
''' <param name="shiftN"></param>
''' <param name="fillValue"></param>
Private Shared Sub ShiftRight(bitArray As BitArray, shiftN As Integer, fillValue As Boolean)
For i As Integer = shiftN To bitArray.Count - 1
bitArray(i - shiftN) = bitArray(i)
Next
'fill the shifted bits as false
For index As Integer = bitArray.Count - shiftN To bitArray.Count - 1
bitArray(index) = fillValue
Next
End Sub
''' <summary>
'''
''' </summary>
''' <param name="bitArray"></param>
''' <returns></returns>
Private Shared Function ConvertToByteArray(bitArray As BitArray) As Byte()
' pack (in this case, using the first bool as the lsb - if you want
' the first bool as the msb, reverse things ;-p)
Dim bytes As Integer = (bitArray.Length + 7) / 8
Dim arr2 As Byte() = New Byte(bytes - 1) {}
Dim bitIndex As Integer = 0
Dim byteIndex As Integer = 0
For i As Integer = 0 To bitArray.Length - 1
If bitArray(i) Then
arr2(byteIndex) = arr2(byteIndex) Or CByte(1 << bitIndex)
End If
bitIndex += 1
If bitIndex = 8 Then
bitIndex = 0
byteIndex += 1
End If
Next
Return arr2
End Function