CURLOPT_DNS_LOCAL_IP4 - IPv4 address to bind DNS resolves to

Added in curl 7.33.0

NULL

Set the local IPv4 address that the resolver should bind to. The argument should be of type char * and contain a single numerical IPv4 address as a string. Set this option to NULL to use the default setting (do not bind to a specific IP address). 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.

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_LOCAL_IP4, "192.168.0.14"); res = curl_easy_perform(curl); curl_easy_cleanup(curl); } }

CURLOPT_DNS_LOCAL_IP4 - IPv4 address to bind DNS resolves to

This option requires that libcurl was built with a resolver backend that supports this operation. The c-ares backend is the only such one.

This functionality affects all supported protocols

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).

CURLOPT_DNS_INTERFACE(3), CURLOPT_DNS_LOCAL_IP6(3), CURLOPT_DNS_SERVERS(3) libcurl 2025-06-16 CURLOPT_DNS_LOCAL_IP4(3)

#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_LOCAL_IP4, char *address);