Finding IP Addresses

[gravyboy]

What's the best way of getting an IP address from a DNS name?

I seem to remember a call GetRemoteAddress . . . .

[da_silvy]

' *** Place the following code inside the form window. ***
 
Private Sub cmdGetIP_Click()
    Dim sockinfo As WSADATA  ' information about Winsock
    Dim hostinfo As HOSTENT  ' information about an Internet host
    Dim pHostinfo As Long    ' pointer to a HOSTENT structure
    Dim pIPAddress As Long   ' pointer to an IP address dword
    Dim ipAddress As Long    ' an IP address, packed into a dword
    Dim pIPString As Long    ' pointer to an IP address formatted as a string
    Dim ipString As String   ' holds a human-readable IP address string
    Dim retval As Long       ' generic return value
    
    ' Open up a Winsock session, using version 2.2.
    retval = WSAStartup(MAKEWORD(2, 2), sockinfo)
    If retval <> 0 Then
        Debug.Print "ERROR: Attempt to open Winsock failed: error"; retval
        Exit Sub
    End If
    
    ' Get information about the domain specified in txtDomain.
    pHostinfo = gethostbyname(txtDomain.Text)
    If pHostinfo = 0 Then
        Debug.Print "Unable to resolve domain name."
    Else
        ' Copy the data into a HOSTENT structure.
        CopyMemory hostinfo, ByVal pHostinfo, Len(hostinfo)
        If hostinfo.h_addrtype <> AF_INET Then
            Debug.Print "A non-IP address was returned."
        Else
            ' Copy the pointer to the first (and probably only) IP address in the structure.
            CopyMemory pIPAddress, ByVal hostinfo.h_addr_list, 4
            ' Copy the actual IP address.
            CopyMemory ipAddress, ByVal pIPAddress, 4
            ' Convert the IP address into a human-readable string.
            pIPString = inet_ntoa(ipAddress)
            ' Copy the result into a string variable.
            ipString = Space(lstrlen(pIPString))
            retval = lstrcpy(ipString, pIPString)
            ' Print the result: a human-readable IP address.
            Debug.Print ipString
        End If
    End If
    
    ' Close the Winsock session.
    retval = WSACleanup()
End Sub
 
'In a module
Public Type WSADATA
    wVersion As Integer
    wHighVersion As Integer
    szDescription As String * 257
    szSystemStatus As String * 129
    iMaxSockets As Long
    iMaxUdpDg As Long
    lpVendorInfo As Long
End Type
Public Declare Function WSAStartup Lib "wsock32.dll" (ByVal wVersionRequested As Integer, lpWSAData _
    As WSADATA) As Long
Public Declare Function WSACleanup Lib "wsock32.dll" () As Long
Public Type HOSTENT
    h_name As Long
    h_aliases As Long
    h_addrtype As Integer
    h_length As Integer
    h_addr_list As Long
End Type
Public Const AF_INET = 2
Public Declare Function gethostbyname Lib "wsock32.dll" (ByVal name As String) As Long
Public Declare Function inet_ntoa Lib "wsock32.dll" (ByVal inaddr As Long) As Long
Public Declare Sub CopyMemory Lib "kernel32.dll" Alias "RtlMoveMemory" (Destination As Any, Source _
    As Any, ByVal length As Long)
Public Declare Function lstrlen Lib "kernel32.dll" Alias "lstrlenA" (ByVal lpString As Any) As Long
Public Declare Function lstrcpy Lib "kernel32.dll" Alias "lstrcpyA" (ByVal lpString1 As Any, ByVal _
    lpString2 As Any) As Long
 
Public Function MAKEWORD(ByVal bLow As Byte, ByVal bHigh As Byte) As Integer
    MAKEWORD = Val("&H" & Right("00" & Hex(bHigh), 2) & Right("00" & Hex(bLow), 2))
End Function