HaProxy: Configuring SNI for a TLS Proxy

If you use HaProxy to e.g. terminate TLS on the frontend and connect via TLS to a backend, one has to take care of sending the SNI (server name indication) extension in the TLS handshake sort of manually. Even if you use host names to address the backend server, e.g. server foobar foobar.example:2342 ssl verify required ca-file /etc/haproxy/ca/foo.crt HaProxy will try to establish the connection…