.\" generated by cd2nroff 0.1 from CURLOPT_HAPROXY_CLIENT_IP.md
.TH CURLOPT_HAPROXY_CLIENT_IP 3 "2026-06-24" libcurl
.SH NAME
CURLOPT_HAPROXY_CLIENT_IP \- set HAProxy PROXY protocol client IP
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HAPROXY_CLIENT_IP,
                          char *client_ip);
.fi
.SH 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 \fIand\fP destination address
of the non\-existing client connection (since 8.20.0).

This option is an alternative to \fICURLOPT_HAPROXYPROTOCOL(3)\fP 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
\fIcorrect\fP data (address) is passed on. libcurl does little to no verification.

Note that if you want to send a \fIdifferent\fP 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.
.SH DEFAULT
NULL, no HAProxy header is sent
.SH PROTOCOLS
This functionality affects all supported protocols
.SH EXAMPLE
.nf
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);
  }
}
.fi
.SH AVAILABILITY
Added in curl 8.2.0
.SH RETURN VALUE
\fIcurl_easy_setopt(3)\fP returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non\-zero means an error occurred, see
\fIlibcurl\-errors(3)\fP.
.SH SEE ALSO
.BR CURLOPT_HAPROXYPROTOCOL (3),
.BR CURLOPT_PROXY (3)