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                     23: .TH CURLOPT_SSL_VERIFYPEER 3 "June 24, 2018" "libcurl 7.70.0" "curl_easy_setopt options"
                     24: 
                     25: .SH NAME
                     26: CURLOPT_SSL_VERIFYPEER \- verify the peer's SSL certificate
                     27: .SH SYNOPSIS
                     28: #include <curl/curl.h>
                     29: 
                     30: CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_VERIFYPEER, long verify);
                     31: .SH DESCRIPTION
                     32: Pass a long as parameter to enable or disable.
                     33: 
                     34: This option determines whether curl verifies the authenticity of the peer's
                     35: certificate. A value of 1 means curl verifies; 0 (zero) means it doesn't.
                     36: 
                     37: When negotiating a TLS or SSL connection, the server sends a certificate
                     38: indicating its identity.  Curl verifies whether the certificate is authentic,
                     39: i.e. that you can trust that the server is who the certificate says it is.
                     40: This trust is based on a chain of digital signatures, rooted in certification
                     41: authority (CA) certificates you supply.  curl uses a default bundle of CA
                     42: certificates (the path for that is determined at build time) and you can
                     43: specify alternate certificates with the \fICURLOPT_CAINFO(3)\fP option or the
                     44: \fICURLOPT_CAPATH(3)\fP option.
                     45: 
                     46: When \fICURLOPT_SSL_VERIFYPEER(3)\fP is enabled, and the verification fails to
                     47: prove that the certificate is authentic, the connection fails.  When the
                     48: option is zero, the peer certificate verification succeeds regardless.
                     49: 
                     50: Authenticating the certificate is not enough to be sure about the server. You
                     51: typically also want to ensure that the server is the server you mean to be
                     52: talking to.  Use \fICURLOPT_SSL_VERIFYHOST(3)\fP for that. The check that the
                     53: host name in the certificate is valid for the host name you're connecting to
                     54: is done independently of the \fICURLOPT_SSL_VERIFYPEER(3)\fP option.
                     55: 
                     56: WARNING: disabling verification of the certificate allows bad guys to
                     57: man-in-the-middle the communication without you knowing it. Disabling
                     58: verification makes the communication insecure. Just having encryption on a
                     59: transfer is not enough as you cannot be sure that you are communicating with
                     60: the correct end-point.
                     61: 
                     62: NOTE: even when this option is disabled, depending on the used TLS backend,
                     63: curl may still load the certificate file specified in
                     64: \fICURLOPT_CAINFO(3)\fP. curl default settings in some distributions might use
                     65: quite a large file as a default setting for \fICURLOPT_CAINFO(3)\fP, so
                     66: loading the file can be quite expensive, especially when dealing with many
                     67: connections. Thus, in some situations, you might want to disable verification
                     68: fully to save resources by setting \fICURLOPT_CAINFO(3)\fP to NULL - but
                     69: please also consider the warning above!
                     70: .SH DEFAULT
                     71: By default, curl assumes a value of 1.
                     72: .SH PROTOCOLS
                     73: All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.
                     74: .SH EXAMPLE
                     75: .nf
                     76: CURL *curl = curl_easy_init();
                     77: if(curl) {
                     78:   curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
                     79: 
                     80:   /* Set the default value: strict certificate check please */
                     81:   curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 1L);
                     82: 
                     83:   curl_easy_perform(curl);
                     84: }
                     85: .fi
                     86: .SH AVAILABILITY
                     87: If built TLS enabled.
                     88: .SH RETURN VALUE
                     89: Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
                     90: .SH "SEE ALSO"
                     91: .BR CURLOPT_SSL_VERIFYHOST "(3), "
                     92: .BR CURLOPT_PROXY_SSL_VERIFYPEER "(3), "
                     93: .BR CURLOPT_PROXY_SSL_VERIFYHOST "(3), "
                     94: .BR CURLOPT_CAINFO "(3), "