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.

<img src="/img/deployment/https/https01.svg">

### TLS Handshake Start

The browser would then communicate with that IP address on **port 443** (the HTTPS port).

你可能拥有一个云服务器（虚拟机）或类似的东西，并且它会有一个<abbr title="That isn't Change">固定</abbr> **公共IP地址**。

在 DNS 服务器中，你可以配置一条记录（“A 记录”）以将 **你的域名** 指向你服务器的公共 **IP 地址**。

这个操作一般只需要在最开始执行一次。

!!! tip
     域名这部分发生在 HTTPS 之前，由于这一切都依赖于域名和 IP 地址，所以先在这里提一下。

### DNS

现在让我们关注真正的 HTTPS 部分。

首先，浏览器将通过 **DNS 服务器** 查询**域名的IP** 是什么，在本例中为 `someapp.example.com`。

DNS 服务器会告诉浏览器使用某个特定的 **IP 地址**。 这将是你在 DNS 服务器中为你的服务器配置的公共 IP 地址。

<img src="/img/deployment/https/https01.svg">

### DNS

Теперь давайте сфокусируемся на работе с HTTPS.

Всё начинается с того, что браузер спрашивает у **DNS-серверов**, какой **IP-адрес связан с доменом**, для примера возьмём домен `someapp.example.com`.

DNS-сервера присылают браузеру определённый **IP-адрес**, тот самый публичный IP-адрес вашего сервера, который вы указали в ресурсной "записи А" при настройке.

<img src="/img/deployment/https/https01.svg">

### TLS Handshake の開始

ブラウザはIPアドレスと**ポート443**（HTTPSポート）で通信します。

通信の最初の部分は、クライアントとサーバー間の接続を確立し、使用する暗号鍵などを決めるだけです。

<img src="/img/deployment/https/https02.svg">

TLS接続を確立するためのクライアントとサーバー間のこのやりとりは、**TLSハンドシェイク**と呼ばれます。

### SNI拡張機能付きのTLS

サーバー内の**1つのプロセス**だけが、特定 の**IPアドレス**の特定の**ポート** で待ち受けることができます。

  * In Istio sidecars, historically we had a lot of client-specific xDS. For example, putting the xDS-client's IP back into the xDS response. This makes efficient control plane implementation (most notably, caching), extremely challenging.
  * In practice, this largely means that references are fully qualified in the API. IP Addresses (generally) have a network associated with them, node names have a cluster associated with them, etc.

### 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`.

/**
 * This test binds two different web servers (IPv4 and IPv6) to the same port, but on different
 * local IP addresses. Requests made to `127.0.0.1` will reach the IPv4 server, and requests made to
 * `::1` will reach the IPv6 server.
 *
 * By orchestrating two different servers with the same port but different IP addresses, we can
 * test what OkHttp does when both are reachable, or if only one is reachable.
 *

   * be logged if the test fails.
   *
   * This client is also configured to be slightly more deterministic, returning a single IP
   * address for all hosts, regardless of the actual number of IP addresses reported by DNS.
   */
  fun newClient(): OkHttpClient {
    var client = testClient
    if (client == null) {
      client =
        initialClientBuilder()

 * addresses nor hostnames; they will be verified as IP addresses (which is a more strict
 * verification).
 */
private val VERIFY_AS_IP_ADDRESS = "([0-9a-fA-F]*:[0-9a-fA-F:.]*)|([\\d.]+)".toRegex()

/** Returns true if this string is not a host name and might be an IP address. */
fun String.canParseAsIpAddress(): Boolean = VERIFY_AS_IP_ADDRESS.matches(this)

/**

Here are some possible combinations and strategies:

* **Gunicorn** managing **Uvicorn workers**
    * Gunicorn would be the **process manager** listening on the **IP** and **port**, the replication would be by having **multiple Uvicorn worker processes**.