# Access Control
This chapter will introduce how to configure the access control policies in EMQX, covering the following topics:
Authentication is the process of verifying the identity of a client. It is an essential part of most applications and can help to protect our services from illegal client connections. EMQX supports several authentication mechanisms to better protect our clients, including:
- Username/password authentication
- JWT authentication
- Enhanced authentication of MQTT 5.0
In EMQX, authorization refers to the permission control over the publish/subscribe operation of the MQTT clients. This chapter will introduce how to use the built-in database, ACL file, or how to integrate with MySQL, PostgreSQL, MongoDB or Redis to configure the authorization rules.
EMQX provides a blacklisting/banning functionality. System admins can block certain clients from accessing EMQX via Dashboard or HTTP API with their client ID, user name, or IP address.