vb 不上ip 138 获取外网IP

我们知道内网ip和外网ip可能不同，这涉及到“网络地址转换”（NAT）。
事实上，*只有*和公网联络才有可能获取外网ip地址，直接用winsock的localip属性，或者ipconfig之类的方法（在内外网ip不同的情况下）获取的都是内网ip！
获取外网ip可以用你说的ip138网页的方式，可以通过winsock、inet、xmlhttp、webbrowser等组件来获取远程服务器返回的数据，即外网ip——从服务器的角度看的你的ip地址。此外也可以使用STUN协议。总之，这些方法都需要处在外网的服务器，因为NAT设备是不会让内网主机获取其ip映射表的。

我可以实现上述提到的每一种获取外网ip的方法。如有需要请追问

vb 如何获取外网ip代码：
'获取公网IP
Private Declare Function InternetOpen Lib "wininet.dll" Alias "InternetOpenA" ( _
ByVal sAgent As String, ByVal lAccessType As Long, _
ByVal sProxyName As String, ByVal sProxyBypass As String, _
ByVal lFlags As Long) As Long
Private Declare Function InternetOpenUrl Lib "wininet.dll" Alias "InternetOpenUrlA" ( _
ByVal hInternetSession As Long, ByVal sUrl As String, _
ByVal sHeaders As String, ByVal lHeadersLength As Long, _
ByVal lFlags As Long, ByVal lContext As Long) As Long
Private Declare Function InternetReadFile Lib "wininet.dll" ( _
ByVal hFile As Long, ByVal sBuffer As String, _
ByVal lNumBytesToRead As Long, _
lNumberOfBytesRead As Long) As Integer
Private Declare Function InternetCloseHandle Lib "wininet.dll" ( _
ByVal hInet As Long) As Integer
Private Const INTERNET_FLAG_NO_CACHE_WRITE = &H4000000
Private Declare Function URLDownloadToFile Lib "urlmon" Alias "URLDownloadToFileA" (ByVal pCaller As Long, ByVal szURL As String, ByVal szFileName As String, ByVal dwReserved As Long, ByVal lpfnCB As Long) As Long

Public Function GetSub() As String
Dim wburl$, wburl2$, X1, X2, X3, X4
On Error GoTo err
wburl = "http://www.ip138.com/ip2city.asp"
wburl = GetUrlFile(wburl)
If InStr(1, wburl, "无法找到该页") = 0 Then
X1 = InStr(1, wburl, "[")
X2 = InStr(1, wburl, "]")
X1 = Mid(wburl, X1, X2 - X1)
X1 = Replace(X1, "[", "")
X1 = Replace(X1, " ", "")
X1 = Replace(X1, vbCrLf, "")
GetSub = X1
Exit Function
End If
wburl2 = "http://www.net.cn/static/customercare/yourIP.asp"
wburl2 = GetUrlFile(wburl2)
If InStr(1, wburl2, "无法找到该页") = 0 Then
X3 = InStr(1, wburl2, "")
X4 = InStr(1, wburl2, "")
X3 = Mid(wburl2, X3, X4 - X3)
X3 = Replace(X3, "", "")
X3 = Replace(X3, " ", "")
X3 = Replace(X3, vbCrLf, "")
GetSub = X3
Exit Function
Else
GetSub = "127.0.0.1"
End If
err:
GetSub = "127.0.0.1"
End Function
Private Function GetUrlFile(stUrl As String) As String
Dim lgInternet As Long, lgSession As Long
Dim stBuf As String * 1024
Dim inRes As Integer
Dim lgRet As Long
Dim stTotal As String
stTotal = vbNullString
lgSession = InternetOpen("VBTagEdit", 1, vbNullString, vbNullString, 0)
If lgSession Then
lgInternet = InternetOpenUrl(lgSession, stUrl, vbNullString, _
0, INTERNET_FLAG_NO_CACHE_WRITE, 0)
If lgInternet Then
Do
inRes = InternetReadFile(lgInternet, stBuf, 1024, lgRet)
stTotal = stTotal & Mid$(stBuf, 1, lgRet)
Loop While (lgRet 0)
End If
inRes = InternetCloseHandle(lgInternet)
End If
GetUrlFile = stTotal
End Function
使用方法：
在form中调用GetSub就行了。
List1.AddItem ("公网IP:" & GetSub + "..")。

原来的http://www.ip138.com获取不了，现在要在原网址末尾增加一个“/ip2city.asp”即可取得啦。完整网址是：http://www.ip138.com/ip2city.asp

如下图所示：