This article aims to provide a general guide on which SSL versions are supported by ASP.NET. As many remote systems (such as payment gateways) enforce TLS 1.2 to be used, you may encounter issues with your .NET application where a lower TLS version is used.
Supported TLS Versions
You can use the below reference table to determine which SSL version your target framework has available.
|.NET Framework Version(s)||Supported SSL Version(s)|
|.NET 3.5 – 4.5.2||SSL3|
TLS 1.2 (With hotfix)
|.NET 3.5 – 4.5.2|
|.NET 4.6 – 4.8||SSL3|
Default TLS Version Used
When using system defaults, the following versions are used for outbound connections:
|.NET Framework Version(s)||Supported SSL Version|
|.NET 3.5 – 4.5.2||Lowest available on operating system (TLS 1.0)|
|.NET 4.6 – 4.8||TLS 1.2|
Conetix also enforces the use of TLS 1.2 for incoming connections.
For .NET versions prior to 4.8, you can enforce TLS 1.2 so that you can make secure connections from your .NET hosting to a remote service (eg, a payment gateway).
If you’re not sure which .NET framework your application can support, we recommend contacting your developers.