Im running a RAC, I tried it on the SCAN and then forced it down the VIP, bypassing the SCAN. Internal or external firewalls not showing any drops. The listener log does not show the connection hitting it for the timeout event. A good start/accept port exchange would take 1-2 seconds max.

Im guessing its not as the client has opened many streams since it opened the start connection and port has closed at that stage. The return is not on the client pcap though. If I search the firewall for the start on the port, I can see it make the start attempt, but it doesnt make the return for over 2 minutes. The external firewall is showing the start packet from the source client IP/port, I then have a 5 second timeout of no traffic that coincides with a 5 second command timeout in the program at which time data starts flowing again. Examining the PCAP for the timeout event, I track the TCP flow, I see it making the attempt out a source port, followed by 2 tcp retransmissions. I set up a connection program that runs every 5 seconds. Windows client > external firewall > internal firewall > database

Examining the PCAP in wireshark, I see tcp retransmission for the tcp flow at timeout event in a packet capture Getting a program intermittently timing out.

Wireshark retransmission