Need Advice on authenticating MQ clients

Document ID : KB000105765
Last Modified Date : 16/07/2018
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MQ client User ID authentication and sample SRVRCONN security exit program 
We are starting to allow MQ Client access to MQ on the mainframe.
We need help understanding how to authenticate the clients. I have been reading in the MQ manuals about an option on the SRVRCONN definition to specify a Security Exit for authentication of the Client User ID. Does CA have any documentation regarding MQ client User ID authentication, or sample SRVRCONN security exit program that you could share with me? 
z/os MQ
CA does not provide any documentation or examples in this area.
The following link on MQseries gives information on finding a free version and paid version of the exit.