CURLOPT_IPRESOLVE - Man Page

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_IPRESOLVE, long resolve);

Allows an application to select what kind of IP addresses to use when establishing a connection or choosing one from the connection pool. This is interesting when using host names that resolve to more than one version of IP.

If the URL provided for a transfer contains a numerical IP version as a host name, this option will not override or prohibit libcurl from using that IP version.

Available values for this option are:

CURL_IPRESOLVE_WHATEVER

Default, can use addresses of all IP versions that your system allows.

CURL_IPRESOLVE_V4

Uses only IPv4 addresses.

CURL_IPRESOLVE_V6

Uses only IPv6 addresses.

CURL_IPRESOLVE_WHATEVER

All

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

  /* of all addresses example.com resolves to, only IPv6 ones are used */
  curl_easy_setopt(curl, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V6);

  ret = curl_easy_perform(curl);

  curl_easy_cleanup(curl);
}

Always

Returns CURLE_OK

CURLOPT_HTTP_VERSION(3), CURLOPT_SSLVERSION(3),

curl_easy_setopt(3), CURLOPT_DNS_SHUFFLE_ADDRESSES(3), CURLOPT_PROXY_SSLVERSION(3), CURLOPT_RESOLVE(3), CURLOPT_SSLVERSION(3), libcurl-security(3).