What does "unauthenticated user" mean in MySQL?

Question

I looked at the active MySQL processes with "mysqladmin proc," and I noticed one or more "unauthenticated user" lines. What does this mean?

Answer

When a user connects to MySQL but has not yet sent their credentials, MySQL does not know the actual user's name yet. Until the user sends its login credentials, MySQL returns "unauthenticated user" in the running process's user column. Once the user is authenticated and sends commands, you should see the correct username.