B4J Question Downgrade TLS1.3 to TLS1.2

[prajinpraveen]

The client is running SAP version that apparently does not work with TLS 1.3
Is it possible to downgrade B4J Non-UI app to use TLS 1.2 instead?

thank you

 

[Erel]

It should work with TLS 1.2 automatically.

Why do you think that this error is related to TLS 1.3?

 

[prajinpraveen]

Apparently that is the problem according to SAP and because I am using B4J they think it our technology

 

[prajinpraveen]

Good Day Erel and everyone,

When I downgrade the Jserver version from Jserver 4.01 to Jserver 3.0, SAP is able to connect successfully.
Here are my findings
B4J 9.80 + Jserver 4.01 ( with HTTPS) - Failure
B4J 9.80 + Jserver 4.01 ( without HTTPS) -Success
B4J 9.80 + Jserver 3.00 ( with/without HTTPS) -Success
B4J 9.30 + Jserver 3.00 ( with/without HTTPS) -Success

Your assistance is highly appreciated

 

[Erel]

Are you using Java 11 with jServer 3?

 

[prajinpraveen]

B4J uses Java version 11
openjdk version "11.0.1" 2018-10-16
OpenJDK Runtime Environment 18.9 (build 11.0.1+13)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.1+13, mixed mode)

QA/Production
openjdk version "19-ea" 2022-09-20
OpenJDK Runtime Environment Zulu19+13-CA (build 19-ea+2)
OpenJDK 64-Bit Server VM Zulu19+13-CA (build 19-ea+2, mixed mode, sharing)

 

[prajinpraveen]

Some more error log

 

[Erel]

My guess is that the problem is with the client. I have many jServer 4 servers running with the default settings.

You can try to exclude TLSv1.3:

'in ConfigureSSL
ssl.As(JavaObject).RunMethod("addExcludeProtocols", Array(Array As String("TLSv1.3")))
srvr.SetSslConfiguration(ssl, SslPort)

I haven't tested it.

 

[prajinpraveen]

Thanks Erel,

I have added this.

Dim jo As JavaObject = ssl
    jo.RunMethod("setExcludeProtocols", Array(Array As String("TLSv1.3")))

I will test with them during the course of the week. your help is much appreciated.

 

[Erel]

If it doesn't work then use jServer3 for now. There is nothing bad with it.

My guess is that at some point their client will be updated and it will start working.