hub client failed to connect - ssl_log_error - Error shutting down SSL connection, [1] error:0x140E0197: SSL routines: SSL_shutdown: shutdown while in init

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)

Issue/Introduction

I have a hub client which is not connecting to a tunnel server.

Other clients are connecting to the tunnel server just fine.

This client was connected before and now it won't connect even if I restart the client.

The only error in the hub log keeps repeating about once per minute:

ssl_log_error - Error shutting down SSL connection, [1] error:0x140E0197: SSL routines: SSL_shutdown: shutdown while in init 

If I restart the tunnel server, the client connects again - but other clients were already connected before the restart without any issue.

Cause

This behavior is related to the way OpenSSL behaves under heavy load.

in OpenSSL, there's a task that creates a session and a task that submits the request for a session. They are independent and neither blocks for the other.

So standard behavior is that you submit a request to open a session and then wait a period of time for it to be completed and then you open your next session.

If the session open didn't complete when you go to start your second session you get this message.

This can occur if the tunnel server is under heavy load and the operating system does not respond quickly enough to requests for sessions.

Resolution

Decrease the total number of tunnel clients connected to the tunnel server, or increase the number and/or power of CPUs on the tunnel server.