placeholder: |
        $ istioctl version
        client version: 1.0.0
        control plane version: 1.0.0
        data plane version: 1.0.0 (100 proxies)
        $ kubectl version
        Client Version: v1.0.0
        Kustomize Version: v1.0.0
        Server Version: v1.0.0
      render: Text
    validations:
      required: true
  - type: textarea

        validator.validate(settings, problems);
        assertEquals(1, problems.messages.size());
        assertContains(
                problems.messages.get(0),
                "'proxies.proxy.id' must be unique" + " but found duplicate proxy with id " + id);
    }

    @Test
    void testValidateProxy() throws Exception {
        Settings settings = new Settings();

	if fwd := r.Header.Get(xForwardedFor); fwd != "" {
		// Only grab the first (client) address. Note that '192.168.0.1,
		// 10.1.1.1' is a valid key for X-Forwarded-For where addresses after
		// the first may represent forwarding proxies earlier in the chain.
		s := strings.Index(fwd, ", ")
		if s == -1 {
			s = len(fwd)
		}
		addr = fwd[:s]
	} else if fwd := r.Header.Get(xRealIP); fwd != "" {

   * * If the proxy selector returns an empty list or null.
   *
   * Otherwise it lists the proxies in the order they will be attempted.
   *
   * @param url a URL with only the scheme, hostname, and port specified.
   */
  open fun proxySelectEnd(
    call: Call,
    url: HttpUrl,
    proxies: List<@JvmSuppressWildcards Proxy>,
  ) {
  }

  /**

				listenerStatus:        lds,
				routeStatus:           rds,
				endpointStatus:        eds,
				extensionconfigStatus: ecds,
			})
			if len(fullStatus) == 0 {
				return nil, nil, fmt.Errorf("no proxies found (checked %d istiods)", len(drs))
			}

			sort.Slice(fullStatus, func(i, j int) bool {
				return fullStatus[i].proxyID < fullStatus[j].proxyID
			})
		}
	}
	if len(mappedResp) > 0 {

 * connection the client has many options:
 *
 *  * **HTTP proxy:** a proxy server may be explicitly configured for the client. Otherwise, the
 *    [proxy selector][java.net.ProxySelector] is used. It may return multiple proxies to attempt.
 *  * **IP address:** whether connecting directly to an origin server or a proxy, opening a socket
 *    requires an IP address. The DNS server may return multiple IP addresses to attempt.
 *

//// tab | Python 3.8+

```Python hl_lines="10"
{!> ../../docs_src/header_params/tutorial002.py!}
```

////

/// warning | "Aviso"

Antes de definir `convert_underscores` como `False`, lembre-se de que alguns proxies e servidores HTTP não permitem o uso de cabeçalhos com sublinhados.

///

## Cabeçalhos duplicados

É possível receber cabeçalhos duplicados. Isso significa, o mesmo cabeçalho com vários valores.

    }

    @Override public void proxySelectStart(Call call, HttpUrl url) {
      printEvent("proxySelectStart");
    }

    @Override public void proxySelectEnd(Call call, HttpUrl url, List<Proxy> proxies) {
      printEvent("proxySelectEnd");
    }

    @Override public void dnsStart(Call call, String domainName) {
      printEvent("dnsStart");
    }

     * @return requested (de-)activation(s) of profile(s) in this execution. Never {@code null}.
     */
    ProfileActivation getProfileActivation();

    // Proxies
    List<Proxy> getProxies();

    MavenExecutionRequest setProxies(List<Proxy> proxies);

    MavenExecutionRequest addProxy(Proxy proxy);

    // Servers
    List<Server> getServers();

///

```Python hl_lines="10"
{!> ../../docs_src/header_params/tutorial002.py!}
```

////

/// warning

Before setting `convert_underscores` to `False`, bear in mind that some HTTP proxies and servers disallow the usage of headers with underscores.

///

## Duplicate headers

It is possible to receive duplicate headers. That means, the same header with multiple values.