we are using MariaDB 10.2.13.0 on Windows Server 2016 for a long time without any problems. Our applications use mysql Connector/NET 184.108.40.206 for connections. The ConnectionString looks like this: Server = localhost; Database=ourDB;Port=3306;Convert Zero Datetime=True;SslMode=None;default command timeout=180.
Lately we have the problem that - but only after weeks - establishing a connection to the database fails. The error message of the server is
[Warning] Aborted connection 1175163 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (Got an error reading communication packets)
At first the problem occurs sporadically, then more and more frequently.
What could be the reason?
Answer Answered by Vladislav Vaintroub in this comment.
a client program (or any program capable of establishing a TCP connection) connected to the server, but did not finish the authentication.
telnet localhost 3306
will suffice after some time, your telnet connection will be closed, you'll see such message in the error log.