Re: should libpq also require TLSv1.2 by default?

I wrote:
> Daniel Gustafsson <daniel(at)yesql(dot)se> writes:
>> SSL_R_UNKNOWN_PROTOCOL seem to covers cases when someone manages to perform
>> something which OpenSSL believes is a broken SSLv2 connection, but their own
>> client-level code use it to refer to SSL as well as TLS. Maybe it's worth
>> adding as a belts and suspenders type thing?

> No objection on my part.

>> If anything it might useful to document in the comment that we're only
>> concerned with TLS versions, SSL2/3 are disabled in the library initialization.

> Good point.

Pushed with those corrections. I also rewrote the comment about which
error codes we'd seen in practice, after realizing that one of my tests
had been affected by the presence of "MinProtocol = TLSv1.2" in
RHEL8's openssl.cnf (causing a max setting less than that to be a local
configuration error, not something the server had rejected).

regards, tom lane