---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_HAPROXY_CLIENT_IP
Section: 3
Source: libcurl
Protocol:
  - All
See-also:
  - CURLOPT_HAPROXYPROTOCOL (3)
  - CURLOPT_PROXY (3)
Added-in: 8.2.0
---

# NAME

CURLOPT_HAPROXY_CLIENT_IP - set HAProxy PROXY protocol client IP

# SYNOPSIS

~~~c
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HAPROXY_CLIENT_IP,
                          char *client_ip);
~~~

# DESCRIPTION

When this parameter is set to a valid IPv4 or IPv6 numerical address in its
printable ASCII string version, the library sends this as the client address
in the HAProxy PROXY protocol v1 header at beginning of the connection.

The client address is reported upstream as the source *and* destination address
of the non-existing client connection (since 8.20.0).

This option is an alternative to CURLOPT_HAPROXYPROTOCOL(3) as that one cannot
use a specified address.

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

The application does not have to keep the string around after setting this
option.

As with most libcurl options, the user of this option must make sure that the
*correct* data (address) is passed on. libcurl does little to no verification.

Note that if you want to send a *different* HAProxy client IP in a subsequent
request, you need to make sure that it is done over a fresh connection as
libcurl does not send it again while reusing connections.

# DEFAULT

NULL, no HAProxy header is sent

# %PROTOCOLS%

# EXAMPLE

~~~c
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    curl_easy_setopt(curl, CURLOPT_HAPROXY_CLIENT_IP, "1.1.1.1");
    result = curl_easy_perform(curl);
  }
}
~~~

# %AVAILABILITY%

# 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).
