[aplorbust]

"They don't reply "hostname not found", or "nope, no such host", or anything similar..."

"hostname not found" was meant to be a general term for failure due to not sending the correct servername when it is required, not a specific protocol error. I apologise for not being more precise. What happens with the non-SNI clients I use in the rare case when absence of correct servername is fatal is that the connection fails. (Most times a correct servername, let alone any servername, is not required1 and the connection succeeds. Thats the point of the original comment: in a majority of cases, its possible to get the page content without using SNI.)

1 As in the case of example.com, for example.

However, I use a local forward proxy for TLS-enabled websites. The proxy returns HTTP 503 error when the connection fails due to SNI. Thus, I do get a consistent "server response" when this happens, albeit not from the remote server.