.\" ************************************************************************** .\" * _ _ ____ _ .\" * Project ___| | | | _ \| | .\" * / __| | | | |_) | | .\" * | (__| |_| | _ <| |___ .\" * \___|\___/|_| \_\_____| .\" * .\" * Copyright (C) 1998 - 2017, Daniel Stenberg, , et al. .\" * .\" * This software is licensed as described in the file COPYING, which .\" * you should have received as part of this distribution. The terms .\" * are also available at https://curl.haxx.se/docs/copyright.html. .\" * .\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell .\" * copies of the Software, and permit persons to whom the Software is .\" * furnished to do so, under the terms of the COPYING file. .\" * .\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY .\" * KIND, either express or implied. .\" * .\" ************************************************************************** .\" .TH CURLOPT_DNS_INTERFACE 3 "May 31, 2017" "libcurl 7.64.0" "curl_easy_setopt options" .SH NAME CURLOPT_DNS_INTERFACE \- set interface to speak DNS over .SH SYNOPSIS #include CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_INTERFACE, char *ifname); .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 (don't bind to a specific interface). The application does not have to keep the string around after setting this option. .SH DEFAULT NULL .SH PROTOCOLS .SH EXAMPLE .nf CURL *curl = curl_easy_init(); if(curl) { curl_easy_setopt(curl, CURLOPT_URL, "http://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), "