## Proxy implementation

In its initial implementations, the ztunnel was actually implemented in 3 different ways: a bespoke Rust implementation, a bespoke Go implementation, and in Envoy.

In the end, [after evaluation](https://docs.google.com/document/d/1c2123cKuYsBDpIon9FFdctWTUIMFweSjgwG7r8l3818/edit), the decision was to move forward with a Rust implementation.

 *
 * Supported on OpenJDK 8 via the JettyALPN-boot library or Conscrypt.
 *
 * Supported on OpenJDK 9+ via SSLParameters and SSLSocket features.
 *
 * ### Trust Manager Extraction
 *
 * Supported on Android 2.3+ and OpenJDK 7+. There are no public APIs to recover the trust
 * manager that was used to create an [SSLSocketFactory].
 *
 * Not supported by choice on JDK9+ due to access checks.
 *
 * ### Android Cleartext Permit Detection

    public static final int NT_STATUS_LOGON_TYPE_NOT_GRANTED = 0xC000015b;
    public static final int NT_STATUS_NO_TRUST_SAM_ACCOUNT = 0xC000018b;
    public static final int NT_STATUS_TRUSTED_DOMAIN_FAILURE = 0xC000018c;
    public static final int NT_STATUS_NOLOGON_WORKSTATION_TRUST_ACCOUNT = 0xC0000199;
    public static final int NT_STATUS_PASSWORD_MUST_CHANGE = 0xC0000224;

    autoscalingv2API: true

  meshConfig:
    enablePrometheusMerge: true

    # The trust domain corresponds to the trust root of a system
    # Refer to https://github.com/spiffe/spiffe/blob/master/standards/SPIFFE-ID.md#21-trust-domain
    trustDomain: "cluster.local"

    defaultConfig:
      proxyMetadata: {}
      tracing:
      #      tlsSettings:

    autoscalingv2API: true

  meshConfig:
    enablePrometheusMerge: true

    # The trust domain corresponds to the trust root of a system
    # Refer to https://github.com/spiffe/spiffe/blob/master/standards/SPIFFE-ID.md#21-trust-domain
    trustDomain: "cluster.local"

    defaultConfig:
      proxyMetadata: {}
      tracing:
      #      tlsSettings:

        "The SAM database on the Windows NT Server does not have a computer account for this workstation trust relationship.",
        "The logon request failed because the trust relationship between the primary domain and the trusted domain failed.",
        "The logon request failed because the trust relationship between this workstation and the primary domain failed.",

  private val sslExcludeFilter =
    Regex(
      buildString {
        append("^(?:")
        append(
          listOf(
            "Inaccessible trust store",
            "trustStore is",
            "Reload the trust store",
            "Reload trust certs",
            "Reloaded",
            "adding as trusted certificates",
            "Ignore disabled cipher suite",
            "Ignore unsupported cipher suite",

    had a crash `IllegalArgumentException: Not a Conscrypt trust manager` because we depended on
    initialization order of companion objects.


## Version 4.7.1

_2020-05-18_

 *  Fix: Pass the right arguments in the trust manager created for `addInsecureHost()`. Without the
    fix insecure hosts crash with an `IllegalArgumentException` on Android.

			Key:         target.KafkaTLS,
			Description: "set to 'on' to enable TLS",
			Optional:    true,
			Type:        "on|off",
		},
		config.HelpKV{
			Key:         target.KafkaTLSSkipVerify,
			Description: `trust server TLS without verification, defaults to "on" (verify)`,
			Optional:    true,
			Type:        "on|off",
		},
		config.HelpKV{
			Key:         target.KafkaClientTLSCert,

### Installing certificates from third party CAs