NAME

       CURLOPT_RESOLVE - provide custom host name to IP address resolves

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_RESOLVE,
                                 struct curl_slist *hosts);

DESCRIPTION

       Pass  a  pointer to a linked list of strings with host name resolve information to use for
       requests with this handle. The linked  list  should  be  a  fully  valid  list  of  struct
       curl_slist  structs  properly  filled  in. Use curl_slist_append(3) to create the list and
       curl_slist_free_all(3) to clean up an entire list.

       Each resolve rule to add should be written using the format

        [+]HOST:PORT:ADDRESS[,ADDRESS]

       HOST is the name libcurl wants to resolve, PORT is the port number of  the  service  where
       libcurl wants to connect to the HOST and ADDRESS is one or more numerical IP addresses. If
       you specify multiple IP addresses they need to be separated by comma. If libcurl is  built
       to  support  IPv6,  each of the ADDRESS entries can of course be either IPv4 or IPv6 style
       addressing.

       This option effectively populates the DNS cache with entries for  the  host+port  pair  so
       redirects  and  everything that operations against the HOST+PORT instead use your provided
       ADDRESS.

       The optional leading "+" specifies that the  new  entry  should  time-out.  Entries  added
       without  the leading plus character never times out whereas entries added with "+HOST:..."
       times out just like ordinary DNS cache entries.

       If the DNS cache already has an  entry  for  the  given  host+port  pair,  the  new  entry
       overrides the former one.

       An  ADDRESS  provided  by  this  option  is  only used if not restricted by the setting of
       CURLOPT_IPRESOLVE(3) to a different IP version.

       To remove names from the DNS cache again, to stop providing these fake resolves, include a
       string in the linked list that uses the format

         -HOST:PORT

       The  entry  to remove must be prefixed with a dash, and the host name and port number must
       exactly match what was added previously.

DEFAULT

       NULL

PROTOCOLS

       All

EXAMPLE

       int main(void)
       {
         CURL *curl;
         struct curl_slist *host = NULL;
         host = curl_slist_append(NULL, "example.com:443:127.0.0.1");

         curl = curl_easy_init();
         if(curl) {
           curl_easy_setopt(curl, CURLOPT_RESOLVE, host);
           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

           curl_easy_perform(curl);

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

         curl_slist_free_all(host);
       }

AVAILABILITY

       Added in 7.21.3. Removal support added in 7.42.0.

       Support for providing the ADDRESS within [brackets] was added in 7.57.0.

       Support for providing multiple IP addresses per entry was added in 7.59.0.

       Support for adding non-permanent entries by using the "+" prefix was added in 7.75.0.

RETURN VALUE

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

SEE ALSO

       CURLOPT_CONNECT_TO(3), CURLOPT_DNS_CACHE_TIMEOUT(3), CURLOPT_IPRESOLVE(3)