I'm working on an issue where a piece of Client software tries to set up a handshake with it's Server side. In the correct scenario, there should be 4 lines:
- TLSv1.2 Client Hello
- TLSv1.2 Server Hello, Certificate, Server Key Exchange, Server Hello Done
- TLSv1.2 Client Key Exchange, Change Cipher Spec, Encrypted Handshake Message
- TLSv1.2 Change Cypher Spec, Encrypted Handshake Message
In the faulting scenario, there's only 2 lines followed by an ACK and a FIN, ACK:
- TLSv1.2 Client Hello
- TLSv1.2 Server Hello, Certificate, Server Key Exchange, Server Hello Done
- TCP [ACK]
- TCP [FIN, ACK]
On the Client side there's an MS Server 2012R2 OS. The odd thing is, some of the same OS machines in the same region work fine.
I would appreciate any clue as to what could be the cause of this.