Error Message: Unable to create agent listener (Address already in use)

"Unable to create agent listener" errors are returned when all ports allocated for agent use (i.e., all ports between PortLow and PortHigh, as set in the active Rulebook) are in use by other processes (including other agent instances) when the Broker tries to launch a new Agent instance.

If you encounter such errors --

  1. Access the Multi-Tier server components installation.
  2. Use a text editor to open your active Rulebook (default, oplrqb.ini). You will generally find this file in the bin sub-directory of your OpenLink server components installation.
  3. Locate the [Protocol TCP] section.
  4. Note the values set for PortLow and PortHigh. Ensure that this range is at least as large as the maximum number of agent instances you will have running simultaneously. We generally recommend allocating an additional 10-100 ports to this range, to allow unrelated processes to consume some ports as assigned by the OS.
  5. Save the Rulebook, restart the Broker, and monitor for recurrence of the error.
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