NAME

       CURLOPT_DNS_SHUFFLE_ADDRESSES - shuffle IP addresses for hostname

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_SHUFFLE_ADDRESSES, long onoff);

DESCRIPTION

       Pass a long set to 1 to enable this option.

       When a name is resolved and more than one IP address is returned, this function shuffles the order of all
       returned addresses so that they are used in a random order. This is similar to the ordering  behavior  of
       the legacy gethostbyname function which is no longer used on most platforms.

       Addresses   are   not   reshuffled   if   name   resolution   is   completed   using   the   DNS   cache.
       CURLOPT_DNS_CACHE_TIMEOUT(3) can be used together with this option to reduce DNS cache timeout or disable
       caching entirely if frequent reshuffling is needed.

       Since  the addresses returned are randomly reordered, the order is not in accordance with RFC 3484 or any
       other deterministic order that may be generated by the system's name resolution implementation. This  may
       have performance impacts and may cause IPv4 to be used before IPv6 or vice versa.

DEFAULT

       0 (disabled)

PROTOCOLS

       This functionality affects all supported protocols

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_DNS_SHUFFLE_ADDRESSES, 1L);

           curl_easy_perform(curl);

           /* always cleanup */
           curl_easy_cleanup(curl);
         }
       }

AVAILABILITY

       Added in curl 7.60.0

RETURN VALUE

       CURLE_OK or an error such as CURLE_UNKNOWN_OPTION.

SEE ALSO

       CURLOPT_DNS_CACHE_TIMEOUT(3), CURLOPT_IPRESOLVE(3)