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.\" ========================================================================
.\"
.IX Title "SSL_CTX_CONFIG 3ossl"
.TH SSL_CTX_CONFIG 3ossl "2026-01-27" "3.5.5" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
SSL_CTX_config, SSL_config \- configure SSL_CTX or SSL structure
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/ssl.h>
\&
\& int SSL_CTX_config(SSL_CTX *ctx, const char *name);
\& int SSL_config(SSL *s, const char *name);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The functions \fBSSL_CTX_config()\fR and \fBSSL_config()\fR configure an \fB\s-1SSL_CTX\s0\fR or
\&\fB\s-1SSL\s0\fR structure using the configuration \fBname\fR.
.PP
By calling \fBSSL_CTX_config()\fR or \fBSSL_config()\fR an application can perform many
complex tasks based on the contents of the configuration file: greatly
simplifying application configuration code. A degree of future proofing
can also be achieved: an application can support configuration features
in newer versions of OpenSSL automatically.
.PP
A configuration file must have been previously loaded, for example using
\&\fBCONF_modules_load_file()\fR. See \fBconfig\fR\|(5) for details of the configuration
file syntax.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBSSL_CTX_config()\fR and \fBSSL_config()\fR return 1 for success or 0 if an error
occurred.
.SH "EXAMPLES"
.IX Header "EXAMPLES"
If the file \*(L"config.cnf\*(R" contains the following:
.PP
.Vb 1
\& testapp = test_sect
\&
\& [test_sect]
\& # list of configuration modules
\&
\& ssl_conf = ssl_sect
\&
\& [ssl_sect]
\& server = server_section
\&
\& [server_section]
\& RSA.Certificate = server\-rsa.pem
\& ECDSA.Certificate = server\-ecdsa.pem
\& Ciphers = ALL:!RC4
.Ve
.PP
An application could call:
.PP
.Vb 4
\& if (CONF_modules_load_file("config.cnf", "testapp", 0) <= 0) {
\&     fprintf(stderr, "Error processing config file\en");
\&     goto err;
\& }
\&
\& ctx = SSL_CTX_new(TLS_server_method());
\&
\& if (SSL_CTX_config(ctx, "server") == 0) {
\&     fprintf(stderr, "Error configuring server.\en");
\&     goto err;
\& }
.Ve
.PP
In this example two certificates and the cipher list are configured without
the need for any additional application code.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBssl\fR\|(7),
\&\fBconfig\fR\|(5),
\&\fBSSL_CONF_cmd\fR\|(3),
\&\fBCONF_modules_load_file\fR\|(3)
.SH "HISTORY"
.IX Header "HISTORY"
The \fBSSL_CTX_config()\fR and \fBSSL_config()\fR functions were added in OpenSSL 1.1.0.
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2015\-2020 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the Apache License 2.0 (the \*(L"License\*(R").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file \s-1LICENSE\s0 in the source distribution or at
<https://www.openssl.org/source/license.html>.
