does TLS support ALPN extension?

0 votes
asked Feb 11, 2019 by smertrios (260 points)

Hi, I need to connect to AWS.IoT using mqtt through port 443 and AWS requires the TLS client to support the ALPN extension to specify the "x-amzn-mqtt-ca" protocol.

Does TlsSocket support ALPN extension? if so, how can I add a custom protocol string?

Thank you.

Applies to: Rebex TLS

1 Answer

0 votes
answered Feb 12, 2019 by Lukas Pokorny (126,910 points)
selected Feb 14, 2019 by smertrios
Best answer

Hi, TlsSocket doesn't support ALPN extension at the moment. However, according to the specification, it looks like adding support for this would be quite simple - we'll add it to one of the next releases.

commented Feb 12, 2019 by smertrios (260 points)
Thank you, Lukas.  Do you have an estimate for when it'll be released? (I'm dependent on this feature for my project.)

Is there any chance to get access to an ALPHA pre-release for testing?
commented Feb 14, 2019 by Lukas Pokorny (126,910 points)
We are currently adding TLS 1.3 support and trying to speed up AES/GCM on non-Windows platforms, so we'll aim to add ALPN support as well during the process. Unfortunately, we are unable to predict the release date at this point.

We'll try to prioritize this to have an alpha/beta with ALPN support next month. I'll keep you updated.
commented Feb 14, 2019 by smertrios (260 points)
much appreciated. thank you.
commented Apr 4, 2019 by smertrios (260 points)
Hi Lukas, is ALPN in the new 2019 R1 release? (I don't see it listed in release notes)
commented Apr 5, 2019 by Lukas Matyska (60,770 points)
Hi, the ALPN extension is not part of 2019 R1. It will be publicly available when TLS 1.3 is released.

However, if you want to receive current beta build (with ALPN) based on 2019 R1, please let us know at
commented Dec 5, 2019 by Lukas Pokorny (126,910 points)
ALPN extension is now supported: