repo/core/curl/files/CURLOPT_DNS_SERVERS.3

.\" generated by cd2nroff 0.1 from CURLOPT_DNS_SERVERS.md
.TH CURLOPT_DNS_SERVERS 3 "2024-09-25" libcurl
.SH NAME
CURLOPT_DNS_SERVERS \- DNS servers to use
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_SERVERS, char *servers);
.fi
.SH DESCRIPTION
Pass a char pointer that is the list of DNS servers to be used instead of the
system default. The format of the dns servers option is:

.nf
host[:port][,host[:port]]...
.fi

For example:

.nf
192.168.1.100,192.168.1.101,3.4.5.6
.fi

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.
.SH DEFAULT
NULL
.SH PROTOCOLS
This functionality affects all supported protocols
.SH EXAMPLE
.nf
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_SERVERS,
                     "192.168.1.100:53,192.168.1.101");
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
.fi
.SH NOTES
This option requires that libcurl was built with a resolver backend that
supports this operation. The c\-ares backend is the only such one.
.SH AVAILABILITY
Added in curl 7.24.0
.SH 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.
.SH SEE ALSO
.BR CURLOPT_DNS_CACHE_TIMEOUT (3),
.BR CURLOPT_DNS_LOCAL_IP4 (3),
.BR CURLOPT_DNS_LOCAL_IP6 (3)