NAME

       CURLOPT_DOH_SSL_VERIFYPEER - verify the DoH SSL certificate

SYNOPSIS

       #include <curl/curl.h>

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

DESCRIPTION

       Pass a long as parameter set to 1L to enable or 0L to disable.

       This  option  tells  curl  to verify the authenticity of the DoH (DNS-over-HTTPS) server's
       certificate. A value of 1 means curl verifies; 0 (zero) means it does not.

       This option is the DoH equivalent of CURLOPT_SSL_VERIFYPEER(3) and only  affects  requests
       to the DoH server.

       When  negotiating  a  TLS or SSL connection, the server sends a certificate indicating its
       identity. Curl verifies whether the certificate is authentic, i.e. that you can trust that
       the  server  is who the certificate says it is.  This trust is based on a chain of digital
       signatures, rooted in certification authority (CA) certificates you supply.  curl  uses  a
       default  bundle of CA certificates (the path for that is determined at build time) and you
       can  specify  alternate  certificates   with   the   CURLOPT_CAINFO(3)   option   or   the
       CURLOPT_CAPATH(3) option.

       When  CURLOPT_DOH_SSL_VERIFYPEER(3)  is  enabled, and the verification fails to prove that
       the certificate is authentic, the connection fails. When the  option  is  zero,  the  peer
       certificate verification succeeds regardless.

       Authenticating  the  certificate  is not enough to be sure about the server. You typically
       also want to ensure that the server  is  the  server  you  mean  to  be  talking  to.  Use
       CURLOPT_DOH_SSL_VERIFYHOST(3)  for that. The check that the hostname in the certificate is
       valid  for  the  hostname  you  are  connecting  to   is   done   independently   of   the
       CURLOPT_DOH_SSL_VERIFYPEER(3) option.

       WARNING:  disabling  verification  of the certificate allows bad guys to man-in-the-middle
       the communication without you knowing it. Disabling verification makes  the  communication
       insecure.  Just  having  encryption on a transfer is not enough as you cannot be sure that
       you are communicating with the correct end-point.

DEFAULT

       1

PROTOCOLS

       This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

       All TLS backends support this option.

EXAMPLE

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

           curl_easy_setopt(curl, CURLOPT_DOH_URL,
                            "https://cloudflare-dns.com/dns-query");

           /* Disable certificate verification of the DoH server */
           curl_easy_setopt(curl, CURLOPT_DOH_SSL_VERIFYPEER, 0L);

           curl_easy_perform(curl);
         }
       }

AVAILABILITY

       Added in curl 7.76.0

RETURN VALUE

       Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

SEE ALSO

       CURLOPT_CAINFO(3),            CURLOPT_CAPATH(3),            CURLOPT_DOH_SSL_VERIFYHOST(3),
       CURLOPT_PROXY_SSL_VERIFYHOST(3),                          CURLOPT_PROXY_SSL_VERIFYPEER(3),
       CURLOPT_SSL_VERIFYHOST(3), CURLOPT_SSL_VERIFYPEER(3)