CURLOPT_DNS_LOCAL_IP4 - Man Page

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_LOCAL_IP4, char *address);

Set the local IPv4 address that the resolver should bind to. The argument should be of type char * and contain a single numerical IPv4 address as a string. Set this option to NULL to use the default setting (do not bind to a specific IP address).

The application does not have to keep the string around after setting this option.

Using this option multiple times makes the last set string override the previous ones. Set it to NULL to disable its use again.

NULL

This functionality affects all supported protocols

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");
    curl_easy_setopt(curl, CURLOPT_DNS_LOCAL_IP4, "192.168.0.14");
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

This option requires that libcurl was built with a resolver backend that supports this operation. The c-ares backend is the only such one.

Added in curl 7.33.0

Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, CURLE_NOT_BUILT_IN if support was disabled at compile-time, or CURLE_BAD_FUNCTION_ARGUMENT when given a bad address.

CURLOPT_DNS_INTERFACE(3), CURLOPT_DNS_LOCAL_IP6(3), CURLOPT_DNS_SERVERS(3)

curl_easy_setopt(3), CURLOPT_DNS_INTERFACE(3), CURLOPT_DNS_LOCAL_IP6(3), CURLOPT_DNS_SERVERS(3), libcurl-symbols(3).