---
title: SSL/TLS input settings
description: These settings apply to SSL/TLS communication between the APM Server and APM Agents. See APM agent TLS communication to learn more. Enable or disable...
url: https://www.elastic.co/docs/solutions/observability/apm/apm-server/ssl-tls-input-settings
products:
  - APM
  - Elastic Observability
applies_to:
  - Elastic Stack: Generally available
---

# SSL/TLS input settings
<note>
  ![supported deployment methods](https://www.elastic.co/docs/solutions/images/observability-binary-yes-fm-yes.svg)Most options on this page are supported by all APM Server deployment methods.
</note>

These settings apply to SSL/TLS communication between the APM Server and APM Agents. See [APM agent TLS communication](https://www.elastic.co/docs/solutions/observability/apm/apm-agent-tls-communication) to learn more.
<tab-set>
  <tab-item title="Fleet-managed">
    Enable TLS in the APM integration settings and use the SSL/TLS input settings to set the path to the server certificate and key.
  </tab-item>

  <tab-item title="APM Server binary">
    The following is a basic APM Server SSL config with secure communication enabled. This will make APM Server serve HTTPS requests instead of HTTP.
    ```yaml
    apm-server.ssl.enabled: true
    apm-server.ssl.certificate: "/path/to/apm-server.crt"
    apm-server.ssl.key: "/path/to/apm-server.key"
    ```

    <tip>
      If APM agents are authenticating themselves using a certificate that cannot be authenticated through known CAs (e.g. self signed certificates), use the `ssl.certificate_authorities` to set a custom CA. This will automatically modify the `ssl.client_authentication` configuration to require authentication.
    </tip>
  </tab-item>
</tab-set>


## Enable TLS

Enable or disable TLS. Disabled by default.

|                   |                          |
|-------------------|--------------------------|
| APM Server binary | `apm-server.ssl.enabled` |
| Fleet-managed     | `Enable TLS`             |


## File path to server certificate

The path to the file containing the certificate for Server authentication. Required if TLS is enabled.

|                   |                                   |
|-------------------|-----------------------------------|
| APM Server binary | `apm-server.ssl.certificate`      |
| Fleet-managed     | `File path to server certificate` |


## File path to server certificate key

The path to the file containing the Server certificate key. Required if TLS is enabled.

|                   |                                       |
|-------------------|---------------------------------------|
| APM Server binary | `apm-server.ssl.key`                  |
| Fleet-managed     | `File path to server certificate key` |


## Key passphrase

The passphrase used to decrypt an encrypted key stored in the configured `apm-server.ssl.key` file.

|                   |                                 |
|-------------------|---------------------------------|
| APM Server binary | `apm-server.ssl.key_passphrase` |
| Fleet-managed     | N/A                             |


## Supported protocol versions

This setting is a list of allowed protocol versions: `SSLv3`, `TLSv1.0`, `TLSv1.1`, `TLSv1.2` and `TLSv1.3`. We do not recommend using `SSLv3` or `TLSv1.0`. The default value is `[TLSv1.1, TLSv1.2, TLSv1.3]`.

|                   |                                      |
|-------------------|--------------------------------------|
| APM Server binary | `apm-server.ssl.supported_protocols` |
| Fleet-managed     | `Supported protocol versions`        |


## Cipher suites for TLS connections

The list of cipher suites to use. The first entry has the highest priority. If this option is omitted, the Go crypto library’s [default suites](https://golang.org/pkg/crypto/tls/) are used (recommended). Note that TLS 1.3 cipher suites are not individually configurable in Go, so they are not included in this list.

|                   |                                     |
|-------------------|-------------------------------------|
| APM Server binary | `apm-server.ssl.cipher_suites`      |
| Fleet-managed     | `Cipher suites for TLS connections` |

The following cipher suites are available:

| Cypher                         | Notes                                     |
|--------------------------------|-------------------------------------------|
| ECDHE-ECDSA-AES-128-CBC-SHA    |                                           |
| ECDHE-ECDSA-AES-128-CBC-SHA256 | TLS 1.2 only. Disabled by default.        |
| ECDHE-ECDSA-AES-128-GCM-SHA256 | TLS 1.2 only.                             |
| ECDHE-ECDSA-AES-256-CBC-SHA    |                                           |
| ECDHE-ECDSA-AES-256-GCM-SHA384 | TLS 1.2 only.                             |
| ECDHE-ECDSA-CHACHA20-POLY1305  | TLS 1.2 only.                             |
| ECDHE-ECDSA-RC4-128-SHA        | Disabled by default. RC4 not recommended. |
| ECDHE-RSA-3DES-CBC3-SHA        |                                           |
| ECDHE-RSA-AES-128-CBC-SHA      |                                           |
| ECDHE-RSA-AES-128-CBC-SHA256   | TLS 1.2 only. Disabled by default.        |
| ECDHE-RSA-AES-128-GCM-SHA256   | TLS 1.2 only.                             |
| ECDHE-RSA-AES-256-CBC-SHA      |                                           |
| ECDHE-RSA-AES-256-GCM-SHA384   | TLS 1.2 only.                             |
| ECDHE-RSA-CHACHA20-POLY1205    | TLS 1.2 only.                             |
| ECDHE-RSA-RC4-128-SHA          | Disabled by default. RC4 not recommended. |
| RSA-3DES-CBC3-SHA              |                                           |
| RSA-AES-128-CBC-SHA            |                                           |
| RSA-AES-128-CBC-SHA256         | TLS 1.2 only. Disabled by default.        |
| RSA-AES-128-GCM-SHA256         | TLS 1.2 only.                             |
| RSA-AES-256-CBC-SHA            |                                           |
| RSA-AES-256-GCM-SHA384         | TLS 1.2 only.                             |
| RSA-RC4-128-SHA                | Disabled by default. RC4 not recommended. |

Here is a list of acronyms used in defining the cipher suites:
- 3DES: Cipher suites using triple DES
- AES-128/256: Cipher suites using AES with 128/256-bit keys.
- CBC: Cipher using Cipher Block Chaining as block cipher mode.
- ECDHE: Cipher suites using Elliptic Curve Diffie-Hellman (DH) ephemeral key exchange.
- ECDSA: Cipher suites using Elliptic Curve Digital Signature Algorithm for authentication.
- GCM: Galois/Counter mode is used for symmetric key cryptography.
- RC4: Cipher suites using RC4.
- RSA: Cipher suites using RSA.
- SHA, SHA256, SHA384: Cipher suites using SHA-1, SHA-256 or SHA-384.


## Curve types for ECDHE based cipher suites

The list of curve types for ECDHE (Elliptic Curve Diffie-Hellman ephemeral key exchange).

|                   |                                             |
|-------------------|---------------------------------------------|
| APM Server binary | `apm-server.ssl.curve_types`                |
| Fleet-managed     | `Curve types for ECDHE based cipher suites` |


## List of root certificates for verifying client certificates

The list of root certificates for verifying client certificates. If `certificate_authorities` is empty or not set, the trusted certificate authorities of the host system are used. If `certificate_authorities` is set, `client_authentication` will be automatically set to `required`. Sending client certificates is currently only supported by the RUM agent through the browser, the Java agent (see [Agent certificate authentication](https://www.elastic.co/docs/reference/apm/agents/java/ssl-configuration)), and the Jaeger agent.

|                   |                                          |
|-------------------|------------------------------------------|
| APM Server binary | `apm-server.ssl.certificate_authorities` |
| Fleet-managed     | N/A                                      |


## Client authentication

This configures what types of client authentication are supported. The valid options are `none`, `optional`, and `required`. The default is `none`. If `certificate_authorities` has been specified, this setting will automatically change to `required`. This option only needs to be configured when the agent is expected to provide a client certificate. Sending client certificates is currently only supported by the RUM agent through the browser, the Java agent (see [Agent certificate authentication](https://www.elastic.co/docs/reference/apm/agents/java/ssl-configuration)), and the Jaeger agent.
- `none` - Disables client authentication.
- `optional` - When a client certificate is given, the server will verify it.
- `required` - Requires clients to provide a valid certificate.


|                   |                                        |
|-------------------|----------------------------------------|
| APM Server binary | `apm-server.ssl.client_authentication` |
| Fleet-managed     | N/A                                    |