CODEWITHSUNDEEP
c#asp.netssl
andreas
andreas

Reputation: 505

SSL Handshake fails from asp.net application - works in browser

I am trying to do a simple get request using the System.Net.Http.HttpClient (using GetStringAsync). The request fails when done from my webapi asp.net application, but it works correctly from the browser and postman.

The request fails with Authentication failed because the remote party has closed the transport stream.

Note: It works correctly when doing get request to other servers using TLS.

I used the following to confirm that the issue was with ssl. Using these two lines makes the request work, but obviously disabling certificate validation is not a real solution.

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
ServicePointManager.ServerCertificateValidationCallback += (sender, cert, chain, sslPolicyErrors) => true;

I tested the server using https://www.ssllabs.com and it seems that everything is working correctly on there. It supports TLS 1.1 and 1.2.

To find out what is going on I was looking at the packages in wireshark, but since I don't know much about ssl, I am not learning much. Looking at the packages from the browser request I can see that it is using the TLS 1.2 protocol and that the handshake looks correct. The following picture shows the client initiating two separate ssl "ClientHello's". For some reason the server doesn't respond with a SSL handshake response.

Wireshark ssl handshake

Hope someone can help me figure out what is going on.

Upvotes: 0

Views: 5228

Answers (1)

Steffen Ullrich
Steffen Ullrich

Reputation: 123531

I tested the server using https://www.ssllabs.com and it seems that everything is working correctly on there. It supports TLS 1.1 and 1.2.

Your client is doing a TLS 1.0 handshake only. If the server supports only TLS 1.1 and TLS 1.2 but not TLS 1.0 the connection will fail. Since modern browsers all support TLS 1.2 browsers will work.

Upvotes: 1

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