server["Server on http://127.0.0.1:8000/app"]

browser --> proxy
proxy --> server
```

/// tip | "Dica"

O IP `0.0.0.0` é comumente usado para significar que o programa escuta em todos os IPs disponíveis naquela máquina/servidor.

///

A interface de documentação também precisaria do OpenAPI schema para declarar que API `server` está localizado em `/api/v1` (atrás do proxy). Por exemplo:

```JSON hl_lines="4-8"

///

## Deployment Concepts

These examples run the server program (e.g Uvicorn), starting **a single process**, listening on all the IPs (`0.0.0.0`) on a predefined port (e.g. `80`).

This is the basic idea. But you will probably want to take care of some additional things, like:

* Security - HTTPS
* Running on startup
* Restarts

// constructor initializes.
func DomainNames(domainNames []string) EtcdOption {
	return func(args *CoreDNS) {
		args.domainNames = domainNames
	}
}

// DomainIPs set a list of custom domain IPs, note this will
// fail if set to empty when constructor initializes.
func DomainIPs(domainIPs set.StringSet) EtcdOption {
	return func(args *CoreDNS) {
		args.domainIPs = domainIPs
	}
}

		switch v := addr.(type) {
		case *net.IPNet:
			ip = v.IP
		case *net.IPAddr:
			ip = v.IP
		}

		if ip.To4() != nil {
			localIP4.Add(ip.String())
		}
	}

	// Filter ipList by IPs those do not start with '127.'.
	nonLoopBackIPs := localIP4.FuncMatch(func(ip string, matchString string) bool {
		return !strings.HasPrefix(ip, "127.")
	}, "")
	if len(nonLoopBackIPs) == 0 {

message IngressRule {
  // host is the fully qualified domain name of a network host, as defined by RFC 3986.
  // Note the following deviations from the "host" part of the
  // URI as defined in RFC 3986:
  // 1. IPs are not allowed. Currently an IngressRuleValue can only apply to
  //    the IP in the Spec of the parent Ingress.
  // 2. The `:` delimiter is not respected because ports are not allowed.

			log.Errorf("istio-cni cmdAdd failed to check ambient: %s", err)
		}

		var prevResIps []*cniv1.IPConfig
		if conf.PrevResult != nil {
			prevResult := conf.PrevResult.(*cniv1.Result)
			prevResIps = prevResult.IPs
		}

		// Only send event if this pod "would be" an ambient-watched pod - otherwise skip
		if podIsAmbient {
			cniEventAddr := filepath.Join(conf.CNIAgentRunDir, constants.CNIEventSocketName)

  // value.
  //
  // This field may hold a maximum of two entries (dual-stack IPs, in either order).
  // These IPs must correspond to the values of the ipFamilies field. Both
  // clusterIPs and ipFamilies are governed by the ipFamilyPolicy field.
  // More info: https://kubernetes.io/docs/concepts/services-networking/service/#virtual-ips-and-service-proxies
  // +listType=atomic
  // +optional

					continue
				}

				// if domain IPs intersect then it won't be an empty set.
				// such an intersection means that bucket exists on etcd.
				// but if we do see a difference with local domain IPs with
				// hostSlice from etcd then we should update with newer
				// domainIPs, we proceed to do that here.
				bucketsToBeUpdated.Add(bucket)
				continue
			}

			// then we will just fail to add the pod to the mesh, and it will be retried later when cni plugin adds it.

			// We need a pod IP - if the pod was added via the CNI plugin, that plugin told us the IPs
			// for the pod. If this is a pod added via informer, the pod should have already gone thru
			// the CNI plugin chain, and have a PodIP.
			//
			// If PodIPs exists, it is preferred, otherwise fallback to PodIP.
			//

proxy["Proxy on http://0.0.0.0:9999/api/v1/app"]
server["Server on http://127.0.0.1:8000/app"]

browser --> proxy
proxy --> server
```

/// tip

The IP `0.0.0.0` is commonly used to mean that the program listens on all the IPs available in that machine/server.

///

The docs UI would also need the OpenAPI schema to declare that this API `server` is located at `/api/v1` (behind the proxy). For example:

```JSON hl_lines="4-8"
{