Error connecting to 10.0.17-MariaDB-1~trusty
I started getting this "Lost connection to MySQL server at 'reading authorization packet'", and after reading https://bugs.mysql.com/bug.php?id=28359 I found out that the client machine (debian 64bits) network interface was in 100Mbps (it is a 1Gb interface and was working in 1Gb, not sure why it fell back to 100Mbps). 

I could "normal ping" and nc, without problems, but a "ping -f -s 10000" from the client to the server would show 1% lost packets.

I disconnected its RJ45, connected it back "pumping" the connector back and forth (it's an old cable/machine, maybe some oxidation had settled in), and changed the switch port, and it auto-negotiated back to 1Gbps.

Then the "ping -f -s 10000" ran ok, and the mysql errors stopped.

So you might check for the connection between client/server. The "normal ping" (small packets may be ok) and nc (may be getting retransmissions, transparent to you) may be working, but a "ping -f -s 10000" can show how it responds under more load. It seems the "Server greeting" phase of the MySql auth does not like dropped packets.

Best regards,