curl / libcurl / API / curl_easy_setopt / CURLOPT_DNS_SERVERS

CURLOPT_DNS_SERVERS explained

Name

CURLOPT_DNS_SERVERS - DNS servers to use

Synopsis

#include <curl/curl.h>
 
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_SERVERS, char *servers);

Description

Pass a char * that is the list of DNS servers to be used instead of the system default. The format of the dns servers option is:

host[:port][,host[:port]]...

For example:

192.168.1.100,192.168.1.101,3.4.5.6

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

Default

NULL - use system default

Protocols

All

Example

CURL *curl = curl_easy_init();
if(curl) {
  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");
  curl_easy_setopt(curl, CURLOPT_DNS_SERVERS, "192.168.1.100:53,192.168.1.101");
  ret = curl_easy_perform(curl);
  curl_easy_cleanup(curl);
}

Availability

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 7.24.0

Return value

Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, CURLE_NOT_BUILT_IN if support was disabled at compile-time, CURLE_BAD_FUNCTION_ARGUMENT when given an invalid server list, or CURLE_OUT_OF_MEMORY if there was insufficient heap space.