CURLOPT_SSL_VERIFYHOST(3)				     curl_easy_setopt options					 CURLOPT_SSL_VERIFYHOST(3)

NAME

       CURLOPT_SSL_VERIFYHOST - verify the certificate's name against host

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_VERIFYHOST, long verify);

DESCRIPTION

       Pass a long as parameter specifying what to verify.

       This option determines whether libcurl verifies that the server cert is for the server it is known as.

       When negotiating TLS and SSL connections, the server sends a certificate indicating its identity.

       When  CURLOPT_SSL_VERIFYHOST(3)	is  2,	that certificate must indicate that the server is the server to which you meant to connect, or the
       connection fails. Simply put, it means it has to have the same name in the certificate as is in the URL you operate against.

       Curl considers the server the intended one when the Common Name field or a Subject Alternate Name field in the certificate matches the host
       name in the URL to which you told Curl to connect.

       When  the  verify value is 1, curl_easy_setopt will return an error and the option value will not be changed.  It was previously (in 7.28.0
       and earlier) a debug option of some sorts, but it is no longer supported due to frequently leading to programmer mistakes. Future  versions
       will stop returning an error for 1 and just treat 1 and 2 the same.

       When the verify value is 0, the connection succeeds regardless of the names in the certificate. Use that ability with caution!

       The default value for this option is 2.

       This  option  controls  checking  the  server's	certificate's  claimed	identity.   The server could be lying.	To control lying, see CUR-
       LOPT_SSL_VERIFYPEER(3).

LIMITATIONS

       DarwinSSL: If verify value is 0, then SNI is also disabled. SNI is a TLS extension that sends the hostname to the server.  The  server  may
       use  that  information  to  do such things as sending back a specific certificate for the hostname, or forwarding the request to a specific
       origin server. Some hostnames may be inaccessible if SNI is not sent.

       NSS: If CURLOPT_SSL_VERIFYPEER(3) is zero, CURLOPT_SSL_VERIFYHOST(3) is also set to zero and cannot be overridden.

DEFAULT

       2

PROTOCOLS

       All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

EXAMPLE

       CURL *curl = curl_easy_init();
       if(curl) {
	 curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

	 /* Set the default value: strict name check please */
	 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 2L);

	 curl_easy_perform(curl);
       }

AVAILABILITY

       If built TLS enabled.

RETURN VALUE

       Returns CURLE_OK if TLS is supported, and CURLE_UNKNOWN_OPTION if not.

       If 1 is set as argument, CURLE_BAD_FUNCTION_ARGUMENT is returned.

SEE ALSO

       CURLOPT_SSL_VERIFYPEER(3), CURLOPT_CAINFO(3),

libcurl 7.54.0							 February 02, 2017					 CURLOPT_SSL_VERIFYHOST(3)