CURLOPT_INTERFACE(3) Library Functions Manual CURLOPT_INTERFACE(3)
NAME
CURLOPT_INTERFACE - source interface for outgoing traffic
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_INTERFACE, char *interface);
DESCRIPTION
Pass a char pointer as parameter. This sets the interface name to use
as outgoing network interface. The name can be an interface name, an IP
address, or a hostname.
If the parameter starts with "if!" then it is treated only as an
interface name. If the parameter starts with "host!" it is treated as
either an IP address or a hostname.
If "if!" is specified but the parameter does not match an existing
interface, CURLE_INTERFACE_FAILED is returned from the libcurl function
used to perform the transfer.
libcurl does not support using network interface names for this option
on Windows.
We strongly advise against specifying the interface with a hostname, as
it causes libcurl to do a blocking name resolve call to retrieve the IP
address. That name resolve operation does not use DNS-over-HTTPS even
if CURLOPT_DOH_URL(3) is set.
The application does not have to keep the string around after setting
this option.
DEFAULT
NULL, use whatever the TCP stack finds suitable
PROTOCOLS
All
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_INTERFACE, "eth0");
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
AVAILABILITY
The "if!" and "host!" syntax was added in 7.24.0.
RETURN VALUE
Returns CURLE_OK on success or CURLE_OUT_OF_MEMORY if there was
insufficient heap space.
SEE ALSO
CURLOPT_LOCALPORT(3), CURLOPT_SOCKOPTFUNCTION(3),
CURLOPT_TCP_NODELAY(3)
libcurl March 28 2024 CURLOPT_INTERFACE(3)
curl 8.7.1 - Generated Mon Apr 1 15:50:08 CDT 2024