NAME

       CURLOPT_DNS_INTERFACE - interface to speak DNS over

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_INTERFACE, char *ifname);

DESCRIPTION

       Pass a char pointer 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.

       Using this option multiple times makes the last set string override the previous ones. Set it to NULL  to
       disable its use again.

DEFAULT

       NULL

PROTOCOLS

       This functionality affects all supported protocols

EXAMPLE

       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_INTERFACE, "eth0");
           res = curl_easy_perform(curl);
           curl_easy_cleanup(curl);
         }
       }

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.

AVAILABILITY

       Added in curl 7.33.0

RETURN VALUE

       curl_easy_setopt(3) returns a CURLcode indicating success or error.

       CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).

SEE ALSO

       CURLOPT_DNS_LOCAL_IP4(3), CURLOPT_DNS_LOCAL_IP6(3), CURLOPT_DNS_SERVERS(3), CURLOPT_INTERFACE(3)

libcurl                                            2025-06-16                           CURLOPT_DNS_INTERFACE(3)