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CURLOPT_DNS_SHUFFLE_ADDRESScurl_easy_setopt opCURLOPT_DNS_SHUFFLE_ADDRESSES(3)


NAME

       CURLOPT_DNS_SHUFFLE_ADDRESSES  -  Shuffle  addresses  when  a  hostname
       returns more than one


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, shuf-
       fle  the order of all returned addresses so that they will be used in a
       random order.  This is similar to the ordering behavior	of  gethostby-
       name 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 implementa-
       tion.  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),

libcurl 7.63.0			March 17, 2018CURLOPT_DNS_SHUFFLE_ADDRESSES(3)

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