TLS message size limit with super tcp channel?

Hi there,
We are working on a huge migration rewriting the server side to .net. Client side is Delphi.
Without SSL enabled the login procedure works. There is a quite huge response on that function. As soon as we enable SSL we get the following behaviour: if the server login function returns the whole response structure - the client remains in the login function until a timeout.

With wireshark we see that if we limit the response on serverside to approx 20kb the client gets the response as expected. If the server delivers the whole structure the clients gets about 27kb and shows the behaviour described above.

Client Delphi 11.1 64bit Remobjects 10.0.0.1537
Server .net 6 Remobjects 10.0.0.1561
Client side uses open SSL 3.

Who does make this limitation and where could one extend it?

Out of curiosity, what happens when you crate a .NET-based client and call the same login method? Does it time out too, or does it work fine? This would help narrow down if the issue is server-side of Delphi-specific on the client side.

What channels are you using, client and server? And also, does the issue persists with the latest version of Remoting SDK for Delphi on the client?

thanx,
marc

Hi Marc,
on server side we use IpSuperTcp. Client side RoSuperTcpChannel.
Since we use wireshark on client side and see there always the limited tcp streamsize - for me its almost impossible that the problem is on the client side.
Right now i’m working on a Delphi/Delphi sample based on a SSL sample from Evgeny found somewehre here.

Hi,

We haven’t any limitations in OpenSSL v3 on Delphi-side.

it would be great if you retested Delphi server vs Delphi client and /or .NET server vs .NET client and confirmed that this issue is .NET or Delphi platform specific.

Hi,
please find a modified Delphi (32bit) server/client project from yourself attached. With enabled SSL support on client and server increase the number of elements to for example 100. Then you will find the client on 100% cpu load until timeout. With 10 elements or disabled SSL everything is as expected.
Its the same behaviour like we use .NET server and Delphi client (so it seems Delphi client related?).
What i’m doing wrong?
Thanks
tls.zip (2.0 MB)

Hi,

I can’t reproduce any issues with your testcase even I use 1000 elements:

Note: you are using an year old version of Remoting SDK for Delphi.
Can you retest this case with the latest version (.1561), pls?

My gosh, updated to 1561 and it works…
Sorry for that. You may delete this thread. Otherwise it maybe useful to know for someone else because it was a very strange behaviour…
Thanks anyway

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