Not possible upload for files >20MB via straight forward HTTPS VS - LTM module only

Hello,

 

We have a Virtual Server on https (no SSL offloading, but a straight forward https) and when users are trying to upload a file bigger than 20MB, it is not possible. If they try to upload that file by-passing the BIG IP it works. It isn't some kind of idle timeout, because application gives the error a second after save button is applied.

 

I can do run a capture, but as traffic is encrypted I don't think that I can see a lot of useful information. To be honest I still don't have knowledge to troubleshoot an application behavior, so even I capture a relevant pcap I cannot really find the issue is on application level.

 

We have one test and one prod environment with cloned setup, so we can test whatever ideas. We can also terminate the SSL on the BIG IP, (re-encryption) so we can clearly see the packet inside if that might help.

 

I would appreciate any ideas you have and also we can test almost everything.

 

It uses a normal tcp profile (I have tried with extended profile to 600sec idle timeout). Persistence profile is Src_addr_1h, but I have also tried with no persistence profile. Also tried with HTTP type + cookie profile. No improvement at all.

 

Best regards, Latchezar