mongo 10.66.187.127:27017/admin -u mongouser -p thepasswordA1

rwuser and mongouser by default to support the MONGODB-CR and SCRAM-SHA-1 authentication methods, respectively.
For those two authentication methods, the shell parameters are not the same. See below for more information.mongouser and all new users created in the console. Shell connection parameters are the same as those described in Quick Start without additional parameters required. See the example below:mongo 10.66.187.127:27017/admin -u mongouser -p thepasswordA1
db directly such as "singer", after connecting to MongoDB, proceed as described below:mongo 10.66.187.127:27017/singer -u mongouser -p thepasswordA1 --authenticationDatabase admin

rwuser, and the authentication method of MONGODB-CR should be expressly specified in the shell connection parameters. See the example below:mongo 10.66.187.127:27017/admin -u rwuser -p thepasswordA1 --authenticationMechanism=MONGODB-CR

db directly such as "singer", after connecting to MongoDB, proceed as described below:mongo 10.66.187.127:27017/singer -u rwuser -p thepasswordA1 --authenticationMechanism=MONGODB-CR --authenticationDatabase admin

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