由于以下错误消息,我们无法使用WebRequest连接到HTTPS服务器:

请求被中止:无法创建SSL/TLS安全通道。

我们知道服务器没有有效的HTTPS证书,但为了绕过这个问题,我们使用下面的代码,我们从另一个StackOverflow帖子:

private void Somewhere() {
    ServicePointManager.ServerCertificateValidationCallback += new RemoteCertificateValidationCallback(AlwaysGoodCertificate);
}

private static bool AlwaysGoodCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors policyErrors) {
   return true;
}

问题是服务器从未验证证书,并出现上述错误而失败。有人知道我该怎么做吗?


我应该提到的是,我和一个同事几周前进行了测试,它运行得很好,与我上面写的类似。我们发现的唯一“主要区别”是,我用的是Windows 7,而他用的是Windows XP。这会改变什么吗?


当前回答

我在尝试访问https://ct.mob0.com/Styles/Fun.png时遇到了这个问题,这是CloudFlare在其CDN上分发的一个图像,支持SPDY和奇怪的重定向SSL证书等疯狂的东西。

我没有像Simons的答案那样指定Ssl3,而是通过下面的Tls12来修复它:

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
new WebClient().DownloadData("https://ct.mob0.com/Styles/Fun.png");

其他回答

在。net 4.5中,这个问题的解决方案是

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

如果你没有。net 4.5,那就使用

ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;

默认的。net ServicePointManager。SecurityProtocol使用SSLv3和TLS协议。如果您正在访问Apache服务器,有一个名为SSLProtocol的配置变量,默认为TLSv1.2。您可以设置ServicePointManager。使用您的web服务器支持的适当协议或更改您的Apache配置以允许所有协议,如SSLProtocolall。

我们在Windows Server 2012R2客户端中遇到了同样的问题。 错误40表示客户端和服务器不同意使用密码套件。 在大多数情况下,服务器需要客户端无法识别的密码套件。

如果你不能修改服务器设置,解决方案是将那些“缺失”的密码套件添加到客户端:

First, go to SSLLabs SSL Labs Enter the url of the site/api you are having problem to connect Wait a few minutes until the test is completed Go to 'Cipher Suites' section and read very carefully TLS 1.3 / TLS 1.2 There you will find the Cipher Suites accepted by the server Now in your windows server, go to Regedit Open the Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Cryptography\Configuration\Local\SSL There you will find 2 folders: 00010002 -->TLS 1.2 and 00010003 --> TLS 1.3 Now, edit the Functions key, and add the suites required by the server In our case, we needed to Add TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 to 00010002 folder

在我的例子中,当一个Windows服务试图连接到一个web服务时,我遇到了这个问题。在Windows事件中,我终于找到了一个错误代码。

事件ID 36888(通道)被引发:

The following fatal alert was generated: 40. The internal error state is 808.

最后,它与Windows热修复有关。在我的例子中是KB3172605和KB3177186

vmware论坛提出的解决方案是在windows中添加一个注册表项。添加以下注册表后,所有工作正常。

[HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ \控制SecurityProviders \ SCHANNEL \ KeyExchangeAlgorithms \ diffie - hellman)

“ClientMinKeyBitLength”= dword: 00000200

显然,这与客户端https握手中缺失的值有关。

列出你的Windows HotFix:

wmic qfe list

解决方案线程:

https://communities.vmware.com/message/2604912#2604912

希望对大家有所帮助。

After days of pulling what hair I have left out, we solved the problem. I tried everything suggested on this post and nothing worked for me. For us, we had a basic .Net Framework 4.8 console app running on a customers Windows VM. The on-premise server we were communicating with required that SSL Certificate Validation was turned off. One of our guys discovered that the server required we were using TLS 1.0 and on the registry settings of the VM, TLS 1.0 was disabled. Once we enabled that, it worked. I also needed to added the following two lines as mentioned many times above:

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls;
ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };