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Re: Understanding the process in which curl access HTTPS server

From: Peng Yu via curl-users <>
Date: Sat, 3 Apr 2021 20:53:10 -0500

On Sat, Apr 3, 2021 at 12:51 PM Ray Satiro via curl-users
<> wrote:
> On 4/3/2021 9:46 AM, Peng Yu via curl-users wrote:
> > I see here is the detail on how curl access https. I also showed how
> > to access it via openssl. But it is not clear how the steps of two
> > processes match each other. Could anybody help understand the detail?
> > Thanks.
> I don't understand the question, can you be more specific?

For example, curl lists those. What openssl output does each row match?

* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
* CAfile: /usr/local/etc/openssl_at_1.1/cert.pem
* CApath: /usr/local/etc/openssl_at_1.1/certs
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):

Received on 2021-04-04