Documentation Home
MySQL Internals Manual

MySQL Internals Manual  /  ...  /  Successful Authentication Successful Authentication

A successful fast authentication path looks as follows:

  1. the client connecting to the server

  2. the server responds with the Initial Handshake Packet using auth method M

  3. the client sends the Handshake Response Packet using the same method M

  4. client and server possibly exchange further packets as required by authentication method M

  5. the server responds with OK_Packet

The packets which server sends in step 4 are the Extra Authentication Data packet prefixed with 0x01, to distinguish them from the OK_Packet or ERR_Packet.


Many authentication methods, including the native mysql password methods, consists of a single challenge--response exchange. In that case no extra packets are exchanged in step 4 and server sends OK_Packet directly after receiving Handshake Response Packet (provided that client is authorized).