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CURLOPT_DNS_SHUFFLE_ADDRESSES(3)    libcurl   CURLOPT_DNS_SHUFFLE_ADDRESSES(3)


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

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

       Addresses will not be reshuffled if a 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 will be reordered randomly, their order
       will not be 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

       All


EXAMPLE

       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 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),

ibcurl 8.1.2                    April 26, 2023
                                              CURLOPT_DNS_SHUFFLE_ADDRESSES(3)

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