tail mongod.log
2017-10-24T14:13:27.180-0400 I CONTROL  [initandlisten]
2017-10-24T14:13:27.180-0400 I CONTROL  [initandlisten] ** WARNING: No SSL certificate validation can be performed since no CA file has been provided
2017-10-24T14:13:27.180-0400 I CONTROL  [initandlisten] **          Please specify an sslCAFile parameter.
2017-10-24T14:13:27.180-0400 I CONTROL  [initandlisten]
2017-10-24T14:13:27.182-0400 I FTDC     [initandlisten] Initializing full-time diagnostic data capture with directory '/data/diagnostic.data'
2017-10-24T14:13:27.182-0400 I NETWORK  [thread1] waiting for connections on port 27017 ssl
2017-10-24T14:13:28.011-0400 I FTDC     [ftdc] Unclean full-time diagnostic data capture shutdown detected, found interim file, some metrics may have been lost. OK
2017-10-24T14:13:29.984-0400 I NETWORK  [thread1] connection accepted from 127.0.0.1:53537 #1 (1 connection now open)
2017-10-24T14:13:29.984-0400 E NETWORK  [conn1] SSL: error:140760FC:SSL routines:SSL23_GET_CLIENT_HELLO:unknown protocol
2017-10-24T14:13:29.984-0400 I -        [conn1] end connection 127.0.0.1:53537 (1 connection now open)