CURLOPT_SSLVERSION(3)      curl_easy_setopt options      CURLOPT_SSLVERSION(3)

NAME
       CURLOPT_SSLVERSION - set preferred TLS/SSL version

SYNOPSIS
       #include <curl/curl.h>

       CURLcode  curl_easy_setopt(CURL  *handle, CURLOPT_SSLVERSION, long ver-
       sion);

DESCRIPTION
       Pass a long as parameter to control which version of SSL/TLS to attempt
       to use.

       Use  one  of  the  available  defines  for  this purpose. The available
       options are:

              CURL_SSLVERSION_DEFAULT
                     The default action. This will attempt to figure  out  the
                     remote SSL protocol version.

              CURL_SSLVERSION_TLSv1
                     TLSv1.x

              CURL_SSLVERSION_SSLv2
                     SSLv2

              CURL_SSLVERSION_SSLv3
                     SSLv3

              CURL_SSLVERSION_TLSv1_0
                     TLSv1.0 (Added in 7.34.0)

              CURL_SSLVERSION_TLSv1_1
                     TLSv1.1 (Added in 7.34.0)

              CURL_SSLVERSION_TLSv1_2
                     TLSv1.2 (Added in 7.34.0)

              CURL_SSLVERSION_TLSv1_3
                     TLSv1.3 (Added in 7.52.0)

              CURL_SSLVERSION_MAX_DEFAULT
                     The flag defines maximum supported TLS version as TLSv1.2
                     or default value from SSL library. Only library NSS  cur-
                     rently  allows  to  get  maximum  supported  TLS version.
                     (Added in 7.54.0)

              CURL_SSLVERSION_MAX_TLSv1_0
                     The  flag  defines  maximum  supported  TLS  version   as
                     TLSv1.0.  (Added in 7.54.0)

              CURL_SSLVERSION_MAX_TLSv1_1
                     The   flag  defines  maximum  supported  TLS  version  as
                     TLSv1.1.  (Added in 7.54.0)

              CURL_SSLVERSION_MAX_TLSv1_2
                     The  flag  defines  maximum  supported  TLS  version   as
                     TLSv1.2.  (Added in 7.54.0)

              CURL_SSLVERSION_MAX_TLSv1_3
                     The   flag  defines  maximum  supported  TLS  version  as
                     TLSv1.3.  (Added in 7.54.0)

DEFAULT
       CURL_SSLVERSION_DEFAULT

PROTOCOLS
       All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

EXAMPLE
       CURL *curl = curl_easy_init();
       if(curl) {
         curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

         /* ask libcurl to use TLS version 1.1 or later */
         curl_easy_setopt(curl, CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1.1 |
                          CURL_SSLVERSION_MAX_DEFAULT);

         /* Perform the request */
         curl_easy_perform(curl);
       }

AVAILABILITY
       SSLv2 is disabled by default since 7.18.1. Other  SSL  versions  avail-
       ability  may  vary depending on which backend libcurl has been built to
       use.

       SSLv3 is disabled by default since 7.39.0.

RETURN VALUE
       Returns CURLE_OK if the option is supported,  and  CURLE_UNKNOWN_OPTION
       if not.

SEE ALSO
       CURLOPT_USE_SSL(3), CURLOPT_HTTP_VERSION(3), CURLOPT_IPRESOLVE(3)

libcurl 7.54.0                 December 13, 2016         CURLOPT_SSLVERSION(3)