}

func runDNSCache(ctx *cli.Context) {
	dnsTTL := ctx.Duration("dns-cache-ttl")
	// Check if we have configured a custom DNS cache TTL.
	if dnsTTL <= 0 {
		if orchestrated {
			dnsTTL = 30 * time.Second
		} else {
			dnsTTL = 10 * time.Minute
		}
	}

	// Call to refresh will refresh names in cache.
	go func() {
		// Baremetal setups set DNS refresh window up to dnsTTL duration.
		t := time.NewTicker(dnsTTL)

    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)

@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))

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

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

  @Test
  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()

	}
	if err == nil && dnsURL != "" {
		bootstrapTraceMsg("initialize remote bucket DNS store")
		globalDNSConfig, err = dns.NewOperatorDNS(dnsURL,
			dns.Authentication(dnsUser, dnsPass),
			dns.RootCAs(globalRootCAs))
		if err != nil {
			configLogIf(ctx, fmt.Errorf("Unable to initialize remote webhook DNS config %w", err))
		}
	}

///

### DNS { #dns }

Теперь сфокусируемся на собственно частях, связанных с HTTPS.

Сначала браузер спросит у **DNS‑серверов**, какой **IP соответствует домену**, в нашем примере `someapp.example.com`.

DNS‑серверы ответят браузеру, какой **конкретный IP‑адрес** использовать. Это будет публичный IP‑адрес вашего сервера, который вы указали в настройках DNS.

#### 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()
    })