///

### DNS

Konzentrieren wir uns nun auf alle tatsächlichen HTTPS-Aspekte.

Zuerst würde der Browser mithilfe der **DNS-Server** herausfinden, welches die **IP für die Domain** ist, in diesem Fall für `someapp.example.com`.

Die DNS-Server geben dem Browser eine bestimmte **IP-Adresse** zurück. Das wäre die von Ihrem Server verwendete öffentliche IP-Adresse, die Sie in den DNS-Servern konfiguriert haben.

///

### DNS { #dns }

Now let's focus on all the actual HTTPS parts.

First, the browser would check with the **DNS servers** what is the **IP for the domain**, in this case, `someapp.example.com`.

The DNS servers would tell the browser to use some specific **IP address**. That would be the public IP address used by your server, that you configured in the DNS servers.

      }

    /**
     * Sets the DNS service used to lookup IP addresses for hostnames.
     *
     * If unset, the [system-wide default][Dns.SYSTEM] DNS will be used.
     */
    fun dns(dns: Dns) =
      apply {
        if (dns != this.dns) {
          this.routeDatabase = null
        }
        this.dns = dns
      }

    /**

 * configure the factory when sample values impact the correctness of the test.
 */
class TestValueFactory : Closeable {
  var taskFaker: TaskFaker = TaskFaker()
  var taskRunner: TaskRunner = taskFaker.taskRunner
  var dns: Dns = Dns.SYSTEM
  var proxy: Proxy = Proxy.NO_PROXY
  var proxySelector: ProxySelector = RecordingProxySelector()
  var proxyAuthenticator: Authenticator = RecordingOkAuthenticator("password", null)

Kotlin calling OkHttp 3.x:

```kotlin
val client = OkHttpClient.Builder()
    .dns { hostname -> InetAddress.getAllByName(hostname).toList() }
    .build()
```

Kotlin calling OkHttp 4.x:

```kotlin
val client = OkHttpClient.Builder()
    .dns(object : Dns {
      override fun lookup(hostname: String) =
          InetAddress.getAllByName(hostname).toList()
    })

#### DNS SRV Records

  @AfterEach
  fun tearDown() {
    factory.close()
  }

  @Test @Disabled
  fun address() {
    val address: Address = factory.newAddress()
    val url: HttpUrl = address.url()
    val dns: Dns = address.dns()
    val socketFactory: SocketFactory = address.socketFactory()
    val proxyAuthenticator: Authenticator = address.proxyAuthenticator()
    val protocols: List<Protocol> = address.protocols()

private fun runBatch(
  dnsProviders: List<DnsOverHttps>,
  names: List<String>,
) {
  var time = System.currentTimeMillis()
  for (dns in dnsProviders) {
    println("Testing ${dns.url}")
    for (host in names) {
      print("$host: ")
      System.out.flush()
      try {
        val results = dns.lookup(host)
        println(results)
      } catch (uhe: UnknownHostException) {
        var e: Throwable? = uhe

        .build(),
    )
    server.enqueue(MockResponse())
    val dns = FakeDns()
    dns["fakeurl"] = client.dns.lookup(server.hostName)
    dns["www.fakeurl"] = client.dns.lookup(server.hostName)
    client =
      client
        .newBuilder()
        .dns(dns)
        .build()
    val call =
      client.newCall(
        Request
          .Builder()

 *
 *  * A DNS lookup failed
 *  * The configuration is incapable of carrying the request, such as when the client is configured
 *    to use `H2_PRIOR_KNOWLEDGE` but the URL's scheme is `https:`.
 *  * Preemptive proxy authentication failed.
 *
 * Planning failures are not necessarily fatal. For example, even if we can't DNS lookup the first