1---
2c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
3SPDX-License-Identifier: curl
4Title: CURLOPT_DNS_INTERFACE
5Section: 3
6Source: libcurl
7See-also:
8  - CURLOPT_DNS_LOCAL_IP4 (3)
9  - CURLOPT_DNS_LOCAL_IP6 (3)
10  - CURLOPT_DNS_SERVERS (3)
11  - CURLOPT_INTERFACE (3)
12---
13
14# NAME
15
16CURLOPT_DNS_INTERFACE - interface to speak DNS over
17
18# SYNOPSIS
19
20~~~c
21#include <curl/curl.h>
22
23CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_INTERFACE, char *ifname);
24~~~
25
26# DESCRIPTION
27
28Pass a char pointer as parameter. Set the name of the network interface that
29the DNS resolver should bind to. This must be an interface name (not an
30address). Set this option to NULL to use the default setting (do not bind to a
31specific interface).
32
33The application does not have to keep the string around after setting this
34option.
35
36# DEFAULT
37
38NULL
39
40# PROTOCOLS
41
42All protocols except file:// - protocols that resolve host names.
43
44# EXAMPLE
45
46~~~c
47int main(void)
48{
49  CURL *curl = curl_easy_init();
50  if(curl) {
51    CURLcode res;
52    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");
53    curl_easy_setopt(curl, CURLOPT_DNS_INTERFACE, "eth0");
54    res = curl_easy_perform(curl);
55    curl_easy_cleanup(curl);
56  }
57}
58~~~
59
60# AVAILABILITY
61
62Added in 7.33.0. This option also requires that libcurl was built with a
63resolver backend that supports this operation. The c-ares backend is the only
64such one.
65
66# RETURN VALUE
67
68Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not,
69or CURLE_NOT_BUILT_IN if support was disabled at compile-time.
70