VB6查找主机名从IP，指定DNS服务器 [英] VB6 Lookup Hostname From IP, Specifying DNS Server

问题描述

我知道如何使用GetHostByAddr Windows API调用从VB中的IPv4查找主机名（这个很棒）。但是，该功能不允许指定要使用的DNS服务器。有时默认公司的DNS服务器是正常的，但其他时候，我需要指定一个外部DNS服务器进行查找，我不认为做一个shell的nslookup和解析输出是最好的方法，这里。

I know how to look up a hostname from an IPv4 in VB using the GetHostByAddr Windows API call (this works great). However, that function does not allow one to specify the DNS server to use. Sometimes the default company DNS servers are fine, but other times I need to specify an external DNS server for lookups, and I don't think doing a shell nslookup and parsing the output is the best method, here.

注意：这实际上将被用作Excel工作簿中的VBA代码，以帮助别人做他的工作，并且当他需要一些简单的功能时，不值得编写一个大的应用程序。

Note: this is actually going to be used as VBA code in an Excel workbook to help someone else do his job, and it's not worth writing a big application when some simple functionality is all he needs.

我认为我可能在API调用中找到了一个答案 getnameinfo ，但仔细阅读似乎表明它不提供servername参数。

I thought I had possibly found an answer in the API call getnameinfo but careful reading seems to indicate it does not offer a servername parameter.

经过激烈的搜索，我发现

After some intense searching, I found reference to the pExtra parameter to the DNSQuery function. But I don't even know how to begin to use that in VB6.

任何人都可以通过从VB6进行DNS查找来帮助我，指定servername使用？

Could anyone help me out in any way with doing a DNS lookup from VB6, specifying the servername to use?

一个全面的解决方案当然会很好，但我愿意工作：只是指向正确的方向。

A full working solution would of course be nice, but I'm willing to work: just point me in the right direction.

更新：由于某些奇怪的原因，它没有单击该DNSQuery是一个Windows API调用。它只是听起来不像一个。如果我收集了一个细节，我肯定会有更多的进展。

UPDATE: For some odd reason it didn't click that DNSQuery was a Windows API call. It just didn't sound like one. I certainly would have been able to make more headway on the problem if I'd gathered that one tiny detail.

推荐答案

尝试这个：

Option Explicit

Private Declare Function DnsQuery Lib "dnsapi" Alias "DnsQuery_A" (ByVal strname As String, ByVal wType As Integer, ByVal fOptions As Long, ByVal pServers As Long, ppQueryResultsSet As Long, ByVal pReserved As Long) As Long
Private Declare Function DnsRecordListFree Lib "dnsapi" (ByVal pDnsRecord As Long, ByVal FreeType As Long) As Long
Private Declare Function lstrlen Lib "kernel32" (ByVal straddress As Long) As Long
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, ByVal Source As Long, ByVal Length As Long)
Private Declare Function inet_ntoa Lib "ws2_32.dll" (ByVal pIP As Long) As Long
Private Declare Function inet_addr Lib "ws2_32.dll" (ByVal sAddr As String) As Long

Private Const DnsFreeRecordList         As Long = 1
Private Const DNS_TYPE_A                As Long = &H1
Private Const DNS_QUERY_BYPASS_CACHE    As Long = &H8

Private Type VBDnsRecord
    pNext           As Long
    pName           As Long
    wType           As Integer
    wDataLength     As Integer
    flags           As Long
    dwTel           As Long
    dwReserved      As Long
    prt             As Long
    others(35)      As Byte
End Type

Private Sub Command1_Click()
    MsgBox Resolve("google.com", "208.67.222.222")
End Sub

Private Function Resolve(sAddr As String, Optional sDnsServers As String) As String
    Dim pRecord     As Long
    Dim pNext       As Long
    Dim uRecord     As VBDnsRecord
    Dim lPtr        As Long
    Dim vSplit      As Variant
    Dim laServers() As Long
    Dim pServers    As Long
    Dim sName       As String

    If LenB(sDnsServers) <> 0 Then
        vSplit = Split(sDnsServers)
        ReDim laServers(0 To UBound(vSplit) + 1)
        laServers(0) = UBound(laServers)
        For lPtr = 0 To UBound(vSplit)
            laServers(lPtr + 1) = inet_addr(vSplit(lPtr))
        Next
        pServers = VarPtr(laServers(0))
    End If
    If DnsQuery(sAddr, DNS_TYPE_A, DNS_QUERY_BYPASS_CACHE, pServers, pRecord, 0) = 0 Then
        pNext = pRecord
        Do While pNext <> 0
            Call CopyMemory(uRecord, pNext, Len(uRecord))
            If uRecord.wType = DNS_TYPE_A Then
                lPtr = inet_ntoa(uRecord.prt)
                sName = String(lstrlen(lPtr), 0)
                Call CopyMemory(ByVal sName, lPtr, Len(sName))
                If LenB(Resolve) <> 0 Then
                    Resolve = Resolve & " "
                End If
                Resolve = Resolve & sName
            End If
            pNext = uRecord.pNext
        Loop
        Call DnsRecordListFree(pRecord, DnsFreeRecordList)
    End If
End Function

这篇关于VB6查找主机名从IP，指定DNS服务器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！