curl / Mailing Lists / curl-library / Single Mail
Buy commercial curl support from WolfSSL. We help you work out your issues, debug your libcurl applications, use the API, port to new platforms, add new features and more. With a team lead by the curl founder himself.

Re: SSL connect error

From: Dan Fandrich via curl-library <>
Date: Wed, 8 Dec 2021 09:03:24 -0800

On Wed, Dec 08, 2021 at 02:53:54PM +0100, Thierry Huchard via curl-library wrote:
> I am the maintainer of the sane-escl backend, I have an error on an https
> access on a canon XK90 scanner.
> If you have an idea of why and how to bypass it, I'm interested!
> curl_handle = curl_easy_init();
> curl_easy_setopt(curl_handle, CURLOPT_URL,
> "");
> curl_easy_setopt(curl_handle, CURLOPT_SSL_VERIFYPEER, 0L);
> curl_easy_setopt(curl_handle, CURLOPT_SSL_VERIFYHOST, 0L);
> curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, memory_callback_c);
> curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)var);
> curl_easy_setopt(curl_handle, CURLOPT_HEADERFUNCTION, header_callback);
> curl_easy_setopt(curl_handle, CURLOPT_HEADERDATA, (void *)header);
> curl_easy_setopt(curl_handle, CURLOPT_FOLLOWLOCATION, 1L);
> curl_easy_setopt(curl_handle, CURLOPT_MAXREDIRS, 3L);
> CURLcode res = curl_easy_perform(curl_handle);
> if (res != CURLE_OK) {
> printf("respond: %s\n", curl_easy_strerror(res)); // respond: SSL
> connect error

Could it be similar to Github issue #5356? Namely, the scanner is running
years-old firmware that uses a long-obsolete TLS version and OpenSSL is
now refusing to talk to it for security reasons? What TLS back-end is your
libcurl using? What TLS version does the scanner want to use?
Received on 2021-12-08