Secure XCOM Windows to z/OS XCOMN0298E Txpi 215 with error 10038

Products

• XCOM Data Transport
• XCOM Data Transport - Windows
• XCOM Data Transport - z/OS

Issue/Introduction

A secure XCOM transfer from Windows to z/OS gives error:
 #XCOMN0298E Unable to allocate remote transaction program: Txpi  215: Socket send error return value = 10038

The XCOM for Windows servers are running under Amazon Web Services (AWS).

Environment

XCOM™ Data Transport® for Windows
XCOM™ Data Transport® for z/OS

Resolution

Even just using the "openssl s_client -connect" command fails to read the z/OS side certificates i.e. this command:
"%XCOM_HOME%\openssl" s_client -connect ##.##.#.#:8045
It takes a long time to return and just shows:
*****
no peer certificate available
---
No client certificate CA names sent

*****

For the attempted transfer, a z/OS TCP trace was captured and viewed in Wireshark.
It showed 3 packets for the expected TCP handshake from the relevant Windows IP address but the expected SSL handshake does not occur after that. It seems something is blocking the SSL handshake process or packets are being dropped.

The root cause turned out to be some network configuration problem which impacted the packets being sent/received for the SSL ping/connection test.