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| .TH CURLOPT_SSLVERSION 3 "September 08, 2021" "libcurl 7.80.0" "curl_easy_setopt options" |
| |
| .SH NAME |
| CURLOPT_SSLVERSION \- preferred TLS/SSL version |
| .SH SYNOPSIS |
| #include <curl/curl.h> |
| |
| CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLVERSION, long version); |
| .SH DESCRIPTION |
| Pass a long as parameter to control which version range of SSL/TLS versions to |
| use. |
| |
| 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. |
| |
| Use one of the available defines for this purpose. The available options are: |
| .RS |
| .IP 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). |
| .IP CURL_SSLVERSION_TLSv1 |
| TLS v1.0 or later |
| .IP CURL_SSLVERSION_SSLv2 |
| SSL v2 - refused |
| .IP CURL_SSLVERSION_SSLv3 |
| SSL v3 - refused |
| .IP CURL_SSLVERSION_TLSv1_0 |
| TLS v1.0 or later (Added in 7.34.0) |
| .IP CURL_SSLVERSION_TLSv1_1 |
| TLS v1.1 or later (Added in 7.34.0) |
| .IP CURL_SSLVERSION_TLSv1_2 |
| TLS v1.2 or later (Added in 7.34.0) |
| .IP CURL_SSLVERSION_TLSv1_3 |
| TLS v1.3 or later (Added in 7.52.0) |
| .RE |
| |
| The maximum TLS version can be set by using \fIone\fP of the |
| CURL_SSLVERSION_MAX_ macros below. It is also possible to OR \fIone\fP of the |
| CURL_SSLVERSION_ macros with \fIone\fP of the CURL_SSLVERSION_MAX_ macros. |
| The MAX macros are not supported for WolfSSL. |
| .RS |
| .IP 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) |
| .IP CURL_SSLVERSION_MAX_TLSv1_0 |
| The flag defines maximum supported TLS version as TLS v1.0. |
| (Added in 7.54.0) |
| .IP CURL_SSLVERSION_MAX_TLSv1_1 |
| The flag defines maximum supported TLS version as TLS v1.1. |
| (Added in 7.54.0) |
| .IP CURL_SSLVERSION_MAX_TLSv1_2 |
| The flag defines maximum supported TLS version as TLS v1.2. |
| (Added in 7.54.0) |
| .IP CURL_SSLVERSION_MAX_TLSv1_3 |
| The flag defines maximum supported TLS version as TLS v1.3. |
| (Added in 7.54.0) |
| .RE |
| |
| In versions of curl prior to 7.54 the CURL_SSLVERSION_TLS options were |
| documented to allow \fIonly\fP the specified TLS version, but behavior was |
| inconsistent depending on the TLS library. |
| |
| .SH DEFAULT |
| CURL_SSLVERSION_DEFAULT |
| .SH PROTOCOLS |
| All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc. |
| .SH EXAMPLE |
| .nf |
| 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); |
| } |
| .fi |
| .SH AVAILABILITY |
| SSLv2 and SSLv3 are refused completely since curl 7.77.0 |
| |
| 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. |
| .SH RETURN VALUE |
| Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. |
| .SH "SEE ALSO" |
| .BR CURLOPT_USE_SSL "(3), " CURLOPT_HTTP_VERSION "(3), " |
| .BR CURLOPT_PROXY_SSLVERSION "(3), " CURLOPT_IPRESOLVE "(3) " |
