The following balancing modes can be used in configuration. They can be defined in listen and frontend sections:
- tcp – Is used for layer 3 balancing. A full-duplex connection will be established between clients and servers, and no layer 7 examination will be performed. This is the default mode. It should be used for SSL, SSH, SMTP.
- Http – Is used for layer 7 balancing. The client request will be analyzed in depth before connecting to any server. Any request which is not RFC-compliant will be rejected. Layer 7 filtering, processing and switching will be possible. This is the mode which brings HAProxy most of its value.
- Health – The instance will work in “health” mode. It will just reply “OK” to incoming connections and close the connection. Nothing will be logged. This mode is used to reply to external components health checks. This mode is deprecated and should not be used anymore as it is possible