@Tag("Slowish")
class DnsOverHttpsTest {
  @RegisterExtension
  val platform = PlatformRule()

  @StartStop
  private val server = MockWebServer()

  private lateinit var dns: Dns
  private val cacheFs = FakeFileSystem()
  private val eventRecorder = EventRecorder()
  private val bootstrapClient =
    OkHttpClient
      .Builder()
      .protocols(listOf(Protocol.HTTP_2, Protocol.HTTP_1_1))

    var routeSelector = newRouteSelector(address)
    dns[PROXY_A_HOST] = dns.allocate(1)
    dns[PROXY_B_HOST] = dns.allocate(1)

    // Mark the ProxyA route as failed.
    val selection = routeSelector.next()
    dns.assertRequests(PROXY_A_HOST)
    val route = selection.next()
    assertRoute(route, address, proxyA, dns.lookup(PROXY_A_HOST, 0), PROXY_A_PORT)
    routeDatabase.failed(route)

    return copy(writeTimeoutMillis = checkDuration("writeTimeout", timeout.toLong(), unit))
  }

  override fun withDns(dns: Dns): Interceptor.Chain {
    check(exchange == null) { "dns can't be adjusted in a network interceptor" }

    return copy(dns = dns)
  }

  override fun withSocketFactory(socketFactory: SocketFactory): Interceptor.Chain {

  @BeforeEach
  fun setUp() {
    socketFactory = SpecificHostSocketFactory(InetSocketAddress(server1.hostName, server1.port))

    client =
      clientTestRule
        .newClientBuilder()
        .dns(dns)
        .socketFactory(socketFactory)
        .eventListenerFactory(clientTestRule.wrap(eventRecorder))
        .build()
  }

  @RepeatedTest(100)
  fun http2OneBadHostOneGoodNoRetryOnConnectionFailure() {

        .addSubjectAlternativeName("differentdns.com")
        .build()
    serverIps = Dns.SYSTEM.lookup(server.hostName)
    dns[server.hostName] = serverIps
    dns["san.com"] = serverIps
    dns["nonsan.com"] = serverIps
    dns["www.wildcard.com"] = serverIps
    dns["differentdns.com"] = listOf()
    val handshakeCertificates =
      HandshakeCertificates
        .Builder()

    object DnsOverride : Override<Dns> {
      override fun Interceptor.Chain.value(): Dns = dns

      override fun Interceptor.Chain.withOverride(value: Dns): Interceptor.Chain = withDns(value)

      override fun OkHttpClient.Builder.withOverride(value: Dns): OkHttpClient.Builder = dns(value)

      override val nonDefaultValue: Dns = Dns { Dns.SYSTEM.lookup(it) }

#### DNS SRV Records

///

### 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.

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()
    })

        if (ro == null || ro.length() == 0) {

            /* No resolveOrder has been specified, use the
             * default which is LMHOSTS,WINS,BCAST,DNS or just
             * LMHOSTS,BCAST,DNS if jcifs.smb1.netbios.wins has not
             * been specified.
             */

            if (nbns == null) {
                resolveOrder = new int[3];