// No cached response.
      if (cacheResponse == null) {
        return CacheStrategy(request, null)
      }

      // Drop the cached response if it's missing a required handshake.
      if (request.isHttps && cacheResponse.handshake == null) {
        return CacheStrategy(request, null)
      }

      // If this response shouldn't have been stored, it should never be used as a response source.

    override val timestampNs: Long,
    override val call: Call,
  ) : CallEvent()

  data class SecureConnectEnd(
    override val timestampNs: Long,
    override val call: Call,
    val handshake: Handshake?,
  ) : CallEvent() {
    override fun closes(event: CallEvent): Boolean = event is SecureConnectStart && call == event.call
  }

  data class ConnectionAcquired(
    override val timestampNs: Long,

        .build();

    Call call = client.newCall(new Request.Builder()
        .url(server.url("/"))
        .build());
    Response response = call.execute();
    System.out.println(response.handshake().tlsVersion());
  }

  public static void main(String... args) throws Exception {
    new HttpsServer().run();
  }

   * client presents a certificate that is [trusted][TrustManager] the handshake will
   * proceed normally. The connection will also proceed normally if the client presents no
   * certificate at all! But if the client presents an untrusted certificate the handshake
   * will fail and no connection will be established.
   */
  fun requestClientAuth() {

    val request = Request.Builder().url("https://mozilla.org/robots.txt").build()

    client.newCall(request).execute().use {
      assertThat(it.protocol).isEqualTo(Protocol.HTTP_2)
      assertThat(it.handshake!!.tlsVersion).isEqualTo(TlsVersion.TLS_1_3)
    }
  }

        .build()

    client.newCall(request).execute().use { response ->
      if (!response.isSuccessful) throw IOException("Unexpected code $response")

      for (certificate in response.handshake!!.peerCertificates) {
        println(CertificatePinner.pin(certificate))
      }
    }
  }
}

fun main() {
  CertificatePinning().run()

import javax.net.ssl.SSLPeerUnverifiedException

/**
 * A certificate chain cleaner that uses a set of trusted root certificates to build the trusted
 * chain. This class duplicates the clean chain building performed during the TLS handshake. We
 * prefer other mechanisms where they exist, such as with
 * [okhttp3.internal.platform.AndroidPlatform.AndroidCertificateChainCleaner].
 *
 * This class includes code from [Conscrypt's][Conscrypt] [TrustManagerImpl] and

	public fun toString ()Ljava/lang/String;
}

public final class okhttp3/Handshake$Companion {
	public final fun -deprecated_get (Ljavax/net/ssl/SSLSession;)Lokhttp3/Handshake;
	public final fun get (Ljavax/net/ssl/SSLSession;)Lokhttp3/Handshake;
	public final fun get (Lokhttp3/TlsVersion;Lokhttp3/CipherSuite;Ljava/util/List;Ljava/util/List;)Lokhttp3/Handshake;
}

        .build();

    try (Response response = client.newCall(request).execute()) {
      if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

      for (Certificate certificate : response.handshake().peerCertificates()) {
        System.out.println(CertificatePinner.pin(certificate));
      }
    }
  }

  public static void main(String... args) throws Exception {
    new CertificatePinning().run();
  }

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

### TLS-Handshake-Start

Der Browser kommuniziert dann mit dieser IP-Adresse über **Port 443** (den HTTPS-Port).