---
name: "CURLOPT_HAPROXY_CLIENT_IP"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLOPT_HAPROXY_CLIENT_IP"
---

# CURLOPT\_HAPROXY\_CLIENT\_IP(3)

set HAProxy PROXY protocol client IP

## NAME

CURLOPT\_HAPROXY\_CLIENT\_IP - set HAProxy PROXY protocol client IP

## SYNOPSIS

```
#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)](/CURLOPT_HAPROXYPROTOCOL/3.md)* 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

This functionality affects all supported protocols

## EXAMPLE

```
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

Added in curl 8.2.0

## RETURN VALUE

*[curl\_easy\_setopt(3)](/curl_easy_setopt/3.md)* returns a CURLcode indicating success or error.

CURLE\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLOPT\_HAPROXYPROTOCOL**(3)](/CURLOPT_HAPROXYPROTOCOL/3.md), [**CURLOPT\_PROXY**(3)](/CURLOPT_PROXY/3.md)