CURLOPT_SSLVERSION(3) Library Functions Manual CURLOPT_SSLVERSION(3)
NAME
CURLOPT_SSLVERSION - preferred TLS/SSL version
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLVERSION, long version);
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:
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 - refused
CURL_SSLVERSION_SSLv3
SSL v3 - refused
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 uses
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.
DEFAULT
CURL_SSLVERSION_DEFAULT
PROTOCOLS
This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS,
POP3S, SMTPS etc.
All TLS backends support this option.
EXAMPLE
int main(void)
{
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, (long)CURL_SSLVERSION_TLSv1);
/* Perform the request */
curl_easy_perform(curl);
}
}
HISTORY
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.
AVAILABILITY
Added in curl 7.1
RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION
if not.
SEE ALSO
CURLOPT_HTTP_VERSION(3), CURLOPT_IPRESOLVE(3),
CURLOPT_PROXY_SSLVERSION(3), CURLOPT_USE_SSL(3)
libcurl 2024-08-05 CURLOPT_SSLVERSION(3)
curl 8.9.1 - Generated Sat Aug 10 12:15:20 CDT 2024