TLS Session Resumption Can Cause Intermittent Connection Failure

1. Run a packet capture (on client and DLB) while reproducing the issue.

2. Examine the Client Hello packet to check if TLS session cache is used. In TLSv1.2, this will be visible in the Session ID field. In TLSv1.3, this will be visible in the PSK extension.

3. If TLS session caching is used on the client side, check if the client has persistence configured. If the client tries to resume a cached TLS session, but sends this request to the "other" DLB worker node (because there is no persistence configured), the connection will be rejected by DLB.

4. To resolve, disable TLS session caching at the client side, or enable persistence.