CURLOPT_DNS_LOCAL_IP4 - IPv4 address to bind DNS resolves to
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 (don't bind to a
specific IP address).
The application does not have to keep the string around after setting this
CURL *curl = curl_easy_init();
curl_easy_setopt(curl, CURLOPT_URL, "http://example.com/foo.bin");
curl_easy_setopt(curl, CURLOPT_DNS_LOCAL_IP4, "192.168.0.14");
ret = curl_easy_perform(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 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.