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.\" **************************************************************************
.\" * _ _ ____ _
.\" * Project ___| | | | _ \| |
.\" * / __| | | | |_) | |
.\" * | (__| |_| | _ <| |___
.\" * \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
.\" *
.\" * This software is licensed as described in the file COPYING, which
.\" * you should have received as part of this distribution. The terms
.\" * are also available at https://curl.haxx.se/docs/copyright.html.
.\" *
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
.\" * copies of the Software, and permit persons to whom the Software is
.\" * furnished to do so, under the terms of the COPYING file.
.\" *
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
.\" * KIND, either express or implied.
.\" *
.\" **************************************************************************
.\"
.TH CURLOPT_SSLVERSION 3 "17 Jun 2014" "libcurl 7.37.0" "curl_easy_setopt options"
.SH NAME
CURLOPT_SSLVERSION \- set 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 of SSL/TLS to attempt to
use.
Use one of the available defines for this purpose. The available options are:
.RS
.IP CURL_SSLVERSION_DEFAULT
The default action. This will attempt to figure out the remote SSL protocol
version.
.IP CURL_SSLVERSION_TLSv1
TLSv1.x
.IP CURL_SSLVERSION_SSLv2
SSLv2
.IP CURL_SSLVERSION_SSLv3
SSLv3
.IP CURL_SSLVERSION_TLSv1_0
TLSv1.0 (Added in 7.34.0)
.IP CURL_SSLVERSION_TLSv1_1
TLSv1.1 (Added in 7.34.0)
.IP CURL_SSLVERSION_TLSv1_2
TLSv1.2 (Added in 7.34.0)
.IP CURL_SSLVERSION_TLSv1_3
TLSv1.3 (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 SSL backends axTLS or wolfSSL.
.RS
.IP CURL_SSLVERSION_MAX_DEFAULT
The flag defines the maximum supported TLS version as TLSv1.2, or the default
value from the SSL library.
(Added in 7.54.0)
.IP CURL_SSLVERSION_MAX_TLSv1_0
The flag defines maximum supported TLS version as TLSv1.0.
(Added in 7.54.0)
.IP CURL_SSLVERSION_MAX_TLSv1_1
The flag defines maximum supported TLS version as TLSv1.1.
(Added in 7.54.0)
.IP CURL_SSLVERSION_MAX_TLSv1_2
The flag defines maximum supported TLS version as TLSv1.2.
(Added in 7.54.0)
.IP CURL_SSLVERSION_MAX_TLSv1_3
The flag defines maximum supported TLS version as TLSv1.3.
(Added in 7.54.0)
.RE
.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 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_IPRESOLVE "(3) "
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