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.TH CURLOPT_DNS_INTERFACE 3 "19 Jun 2014" libcurl libcurl
.SH NAME
CURLOPT_DNS_INTERFACE \- interface to speak DNS over
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_INTERFACE, char *ifname);
.fi
.SH DESCRIPTION
Pass a char * as parameter. Set the name of the network interface that the DNS
resolver should bind to. This must be an interface name (not an address). Set
this option to NULL to use the default setting (do not bind to a specific
interface).

The application does not have to keep the string around after setting this
option.
.SH DEFAULT
NULL
.SH PROTOCOLS
All protocols except file:// - protocols that resolve host names.
.SH EXAMPLE
.nf
CURL *curl = curl_easy_init();
if(curl) {
  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");
  curl_easy_setopt(curl, CURLOPT_DNS_INTERFACE, "eth0");
  ret = curl_easy_perform(curl);
  curl_easy_cleanup(curl);
}
.fi
.SH AVAILABILITY
Added in 7.33.0. This option also requires that libcurl was built with a
resolver backend that supports this operation. The c-ares backend is the only
such one.
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not,
or CURLE_NOT_BUILT_IN if support was disabled at compile-time.
.SH "SEE ALSO"
.BR CURLOPT_DNS_SERVERS "(3), " CURLOPT_DNS_LOCAL_IP4 "(3), "