xenial (3) CURLOPT_SSL_VERIFYHOST.3.gz

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   CURLOPT_SSL_VERIFYPEER(3).    If   libcurl   is   built   against  NSS  and
       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),