Two major proxy modes are supported: "tcp", also known as layer 4 and "http" known as layer 7.
"tcp" Proxy Mode
In "tcp" mode, HAProxy forwards bidirectional traffic between two sides.
"http" Proxy Mode
In "http" mode, HAProxy analyzes the protocol and can interact with it by allowing, blocking, switching, adding, modifying or removing arbitrary contents in requests or responses.
HAProxy does not write log information on disk, but it forwards it to the syslog server, over UDP, by default on port 514.
- HAProxy Logging Configuration
Connection Health Check
HAProxy can be configured to terminate the SSL connection or to pass it through the backend server.
When HAProxy is configured with SSL pass-through
, the backend servers handle the SSL connection, rather than the load balancer. The load balancer will just simply proxy the request off to its backend server. The connection will remain encrypted, and the load balancer cannot see what it contains. The frontend will have to be configured in "tcp" mode
. For more details on configuration, see:
- HAProxy SSL Pass-Through Configuration