title: AWS DMS issue with source endpoint in EC2-classic
body: <p>We are using several EC2-Classic servers (Linux Ubuntu) with following configuration: mounted EBS volumes and on them is running Server version: 5.5.48-MariaDB</p>
  
  <p>I would like to use AWS DMS (AWS Database Migration Service) and to migrate our EBS DBs to the RDS AuroraDB in new VPC.
  I created VPC, AuroraDB (not public accessible), AWS DMS replication instance and endpoints. </p>
  
  <p>From EC2-classic instance I am able to open remote AuroraDB console (thanks to Classic Link), which is in the VPC.
  Target endpoint (to the AuroraDB) works OK and TEST was finished successful</p>
  
  <p>Source Endpoint show me following error:</p>
  
  <pre><code>Operation:testEndpointDetails:[errType=ERROR_RESPONSE,
  status=122502, errMessage=Cannot connect to ODBC provider 122502 ODBC general error.,
  errDetails= RetCode: SQL_ERROR SqlState: HY000 NativeError: 2003 Message: unixODBCMySQL http://ODBC 5.3(w)
  DriverCan't connect to MySQL server on 'Private.DNS.name' (110) http://122502] ODBC general error.
  </code></pre>
  
  <p>I tried to set like Server name
  Private/Public DNS, and Private/Public IP, still same.</p>
  
  <p>Credentials are OK, and I am not using any special characters. 
  I am operate in North Virginia Region. 
  AWS DMS replication instance is set as Public. 
  I am able to log into MariaDB console from remote EC2-classic instance.</p>
  
  <p>I tried set port 3306 and Private/Public IP of AWS DMS replication instance into right Security Groups, but I guess that I still miss something, probably in the SG area, but I am not sure.</p>