GNURLOPT_SSLVERSION(3)

okay so bestie 💖 welcome to the GNURLOPT_SSLVERSION(3) page — it's part of the curl_easy_setopt options crew, and we're about to make TLS version picking make sense. no cap, this one is lowkey iconic for controlling your SSL/TLS vibe. 🦋

✨ NAME ✨

CURLOPT_SSLVERSION — set preferred TLS/SSL version

🌸 SYNOPSIS 🌸

#include <gnurl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLVERSION, long
       version);

💅 DESCRIPTION 💅

Pass a long as the parameter to control which version range of SSL/TLS versions to use. literally the range, bestie. ✨

The SSL and TLS versions have typically developed from the most insecure version to be more and more secure in this order through history: SSL v2, SSLv3, TLS v1.0, TLS v1.1, TLS v1.2 and the most recent TLS v1.3. it's giving a whole security glow-up timeline. 👑

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

• CURL_SSLVERSION_DEFAULT — The default acceptable version range. The minimum acceptable version is by default TLS v1.0 since 7.39.0 (unless the TLS library has a stricter rule).
• CURL_SSLVERSION_TLSv1 — TLS v1.0 or later
• CURL_SSLVERSION_SSLv2 — SSL v2 (but not SSLv3)
• CURL_SSLVERSION_SSLv3 — SSL v3 (but not SSLv2)
• CURL_SSLVERSION_TLSv1_0 — TLS v1.0 or later (Added in 7.34.0)
• CURL_SSLVERSION_TLSv1_1 — TLS v1.1 or later (Added in 7.34.0)
• CURL_SSLVERSION_TLSv1_2 — TLS v1.2 or later (Added in 7.34.0)
• CURL_SSLVERSION_TLSv1_3 — TLS v1.3 or later (Added in 7.52.0)

The maximum TLS version can be set by using one of the CURL_SSLVERSION_MAX_ macros below. It is also possible to OR one of the CURL_SSLVERSION_ macros with one of the CURL_SSLVERSION_MAX_ macros. The MAX macros are not supported for WolfSSL. 🐺

• CURL_SSLVERSION_MAX_DEFAULT — The flag defines the maximum supported TLS version by libcurl, or the default value from the SSL library is used. libcurl will use a sensible default maximum, which was TLS v1.2 up to before 7.61.0 and is TLS v1.3 since then - assuming the TLS library support it. (Added in 7.54.0)
• CURL_SSLVERSION_MAX_TLSv1_0 — The flag defines maximum supported TLS version as TLS v1.0. (Added in 7.54.0)
• CURL_SSLVERSION_MAX_TLSv1_1 — The flag defines maximum supported TLS version as TLS v1.1. (Added in 7.54.0)
• CURL_SSLVERSION_MAX_TLSv1_2 — The flag defines maximum supported TLS version as TLS v1.2. (Added in 7.54.0)
• CURL_SSLVERSION_MAX_TLSv1_3 — The flag defines maximum supported TLS version as TLS v1.3. (Added in 7.54.0)

In versions of curl prior to 7.54 the CURL_SSLVERSION_TLS options were documented to allow only the specified TLS version, but behavior was inconsistent depending on the TLS library. so yeah, historical messiness — noted. 😭

🎀 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 1.0 or later */
  curl_easy_setopt(curl, CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1);

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

⭐ AVAILABILITY ⭐

SSLv2 is disabled by default since 7.18.1. Other SSL versions availability 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_PROXY_SSLVERSION(3)
• CURLOPT_IPRESOLVE(3)

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mwah 💋 this page is from libcurl 7.37.0, dated 17 Jun 2014 — catch you in the next manpage, bestie 🫶