.NET和ServicePointManager.SecurityProtocol

Question

我正在使用.net中的webclient类，并且我下载了一个站点。

Dim oWebClient As New WebClient()
Dim oDownloadedPage As String = oWebClient.DownloadString(<site>)

它抛出了一个身份验证错误，在稍微搜索了一下后，我发现我试图下载的站点必须禁用了TLS1.0

所以我把ServicePointManger改成了这样

ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 Or 
   SecurityProtocolType.Tls12 Or SecurityProtocolType.Tls11 Or SecurityProtocolType.Tls

我得到了同样的错误..所以我决定把它改成这样..

ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 Or 
   SecurityProtocolType.Tls Or SecurityProtocolType.Tls11 Or SecurityProtocolType.Tls12

看到我在那里做了什么了吗？我调换了顺序，然后它就起作用了。

有人能给我解释一下顺序有什么区别吗？为什么这很重要？我想知道如果我去下载一个TLS1.0站点，如果它会失败。

Answer 1

System.Net.ServicePointManager.SecurityProtocol = DirectCast(3072, System.Net.SecurityProtocolType) 'TLS 1.2
Dim inStream As StreamReader
Dim webRequest As WebRequest
Dim webresponse As WebResponse
Dim cResult As String = ""
dim cURL as String="https://your.page.com"
webRequest = WebRequest.Create(cURL)
webresponse = webRequest.GetResponse()
inStream = New StreamReader(webresponse.GetResponseStream())
cResult = inStream.ReadToEnd()

这对我来说很有效！