When will fiddler classic support tls1.3?

[chen]

I user fiddler classic as proxy and it works well.

i try to use it to access https://link.springer.com/ iget this:

System.Security.SecurityException Failed to negotiate HTTPS connection with server.fiddler.network.https> HTTPS handshake to link.springer.com

This is because fiddler classic does not yet support tls 1.3. When will fiddler classic be updated to support tls1.3?

thanks so much!

[Rosen Vladimirov]

The TLS 1.3 support is logged as a feature request in our feedback portal. You can track its progress here: https://feedback.telerik.com/fiddler/1584209-support-tls-1-3-now-that-net-framework-does We cannot give an estimate when this feature will be implemented.

Regarding your specific use-case - https://link.springer.com/  we've tried accessing and it seems to work correctly on our side when Fiddler Classic captures traffic - we've tested on Windows 11 and Windows 10. So maybe something else fails on your side or we'll need more details how to reproduce the problem on our side.

[chen]

Thanks for reply.

I try Fiddler Classic on my home pc, it works well.

But in my company it get the same error System.Security.SecurityException Failed to negotiate HTTPS connection with server.fiddler.network.https> HTTPS handshake to link.springer.com

This maybe the company's server os is windows server 2008. I will try fiddler classic on windows server 2019.

I really hope fiddler classic will support TLS 1.3.

Thanks again.

[Nick Iliev]

Hey Chen,

 

It looks like the server at springer.com supports both TLS 1.2 and TLS 1.3 (tested here). Please ensure that Windows Server 2008 and Fiddler Classic are configured to use TLS 1.2.

For Fiddler Classic,  you can check and enable the TLS 1.2 support through the Tools > Options >  HTTPS > Protocols option.


You can click on the list and explicitly set the supported protocol versions (ensure that TLS 1.2 is added).

For example, you can add:

<client>;ssl3;tls1.0;tls1.1;tls1.2

And in the end, it should look like this:

 

Older versions of Windows Server 2008 are not supporting TLS 1.2 by default. As noted here, a patch enables the support for TLS 1.2 in Windows Server 2008 R2. Even with the patch installed, the support for TLS 1.2 is disabled by default in Windows Server 2008 R2.

This post is authored by Arden White, Senior Program Manager, Windows Servicing and Delivery.

As a follow-up to our announcement regarding TLS 1.2 support at Microsoft we are announcing that support for TLS1.1/TLS 1.2 on Windows Server 2008 is now available for download as of July 18th, 2017. We’re offering this support in recognition that our customers have a strong demand for support for these newer protocols in their environment and in recognition of the extended lifetime of Windows Server 2008 under the Windows Server Premium Assurance offering.

This update for Windows Server 2008 will include support for both TLS 1.1 and TLS 1.2. For application compatibility purposes, these protocols will be disabled by default in a manner similar to the TLS 1.1/TLS 1.2 support that was disabled by default in Windows 7 and Windows Server 2008 R2. After downloading and installing the update these protocols can be enabled by setting the registry keys described in KB4019276.

The above said we would expect the handshake to complete successfully if both Windows Server 2008 R2 and Fiddler can use TLS 1.2 and if the server does not explicitly require a TLS 1.3 connection. Note that even if Fiddler Classic adds support for TLS 1.3, it probably won't solve your specific issue because Windows Server 2008 does not officially support TLS 1.3 and the OS reached the End-of-Support date declared from Microsoft in 2020 (meaning no new features are planned or released).