Table of Contents

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  1. Preface
  2. Introduction to PowerExchange
  3. DBMOVER Configuration File
  4. Netport Jobs
  5. PowerExchange Message Logs and Destination Overrides
  6. SMF Statistics Logging and Reporting
  7. PowerExchange Security
  8. Secure Sockets Layer Support
  9. PowerExchange Alternative Network Security
  10. PowerExchange Nonrelational SQL
  11. PowerExchange Globalization
  12. Using the PowerExchange ODBC Drivers
  13. PowerExchange Datatypes and Conversion Matrix
  14. Appendix A: DTL__CAPXTIMESTAMP Time Stamps
  15. Appendix B: PowerExchange Glossary

TCPIP_ACCEPT_NONBLOCK Statement

TCPIP_ACCEPT_NONBLOCK Statement

The TCPIP_ACCEPT_NONBLOCK statement specifies whether the TCP/IP ports on which the PowerExchange Listener listens are blocking or nonblocking ports.
Define TCPIP_ACCEPT_NONBLOCK=Y if the following conditions apply:
  • You perform a security check by using a port scanner such as Nessus.
  • The PowerExchange Listener appears to hang indefinitely on the main Listener port or ignore commands.
  • A Listener port for a netport job is defined.
z/OS
No
TCPIP_ACCEPT_NONBLOCK={
N
|Y}
  • N
    .
    PowerExchange Listener listening ports are blocking ports. When a blocking port is accessed, it blocks other attempts to access the port.
  • Y.
    PowerExchange Listener listening ports are nonblocking ports.
Default is N.
If you perform a security check by using a port scanner such as Nessus, the PowerExchange Listener might hang indefinitely on the main Listener port or ignore commands if a Listener port for a netport job is also defined. The problem occurs when a call to the TCPIP accept() function on the netport port is blocked until a connection is present. While the netport port is blocked, the main PowerExchange Listener port is never polled, so that non-netport requests appear to be hung. The Listener remains in this state until a subsequent netport request unblocks the netport port.
If this situation occurs, include the TCPIP_ACCEPT_NONBLOCK=Y statement in the DBMOVER configuration file on the Listener machine. This statement makes the PowerExchange Listener listening ports nonblocking, so that the accept() call can return a suitable status if it fails.