---
layout: "docs"
page_title: "Connect - Configuration"
sidebar_current: "docs-connect-config"
description: |-
  A Connect-aware proxy enables unmodified applications to use Connect. A per-service proxy sidecar transparently handles inbound and outbound service connections, automatically wrapping and verifying TLS connections.
---

# Connect Configuration

There are many configuration options exposed for Connect. The only option
that must be set is the "enabled" option on Consul Servers to enable Connect.
All other configurations are optional and have reasonable defaults.

## Enable Connect on the Cluster

The first step to use Connect is to enable Connect for your Consul
cluster. By default, Connect is disabled. Enabling Connect requires changing
the configuration of only your Consul _servers_ (not client agents). To enable
Connect, add the following to a new or existing
[server configuration file](/docs/agent/options.html). In HCL:

```hcl
connect {
  enabled = true
}
```

This will enable Connect and configure your Consul cluster to use the
built-in certificate authority for creating and managing certificates.
You may also configure Consul to use an external
[certificate management system](/docs/connect/ca.html), such as
[Vault](https://vaultproject.io).

-> **Security note:** Enabling Connect is enough to try the feature but doesn't
automatically ensure complete security. Please read the [Connect production
guide](/docs/guides/connect-production.html) to understand the additional steps
needed for a secure deployment.

No agent-wide configuration is necessary for non-server agents. Services
and proxies may always register with Connect settings, but they will fail to
retrieve or verify any TLS certificates. This causes all Connect-based
connection attempts to fail until Connect is enabled on the server agents.

-> **Note:** Connect is enabled by default when running Consul in
dev mode with `consul agent -dev`.

## Built-In Proxy Options

This is complete example of all the configuration options available for the
built-in proxy. Note that only the `service.connect.proxy.config` map is being
described here, the rest of the service definition is shown for context and is
[described elsewhere](/docs/connect/proxies.html#managed-proxies).

```javascript
{
  "service": {
    "name": "web",
    "port": 8080,
    "connect": {
      "proxy": {
        "config": {
          "bind_address": "0.0.0.0",
          "bind_port": 20000,
          "local_service_address": "127.0.0.1:1234",
          "local_connect_timeout_ms": 1000,
          "handshake_timeout_ms": 10000,
          "upstreams": [
            {
              "destination_type": "service",
              "destination_name": "redis",
              "destination_datacenter": "dc1",
              "local_bind_address": "127.0.0.1",
              "local_bind_port": 1234,
              "connect_timeout_ms": 10000
            },
          ]
        }
      }
    }
  }
}
```

#### Configuration Key Reference

* <a name="bind_address"></a><a href="#bind_address">`bind_address`</a> -
  The address the proxy will bind it's _public_ mTLS listener to. It
  defaults to the same address the agent binds to.

* <a name="bind_port"></a><a href="#bind_port">`bind_port`</a> - The
  port the proxy will bind it's _public_ mTLS listener to. If not provided, the
  agent will attempt to assing one from its [configured proxy port
  range](/docs/agent/options.html#proxy_min_port) if available. By default the
  range is [20000, 20255] and the port is selected at random from that range.

* <a name="local_service_address"></a><a href="#local_service_address">`local_service_address`</a>
  - The `[address]:port` that the proxy should use to connect to the
    local application instance. By default it assumes `127.0.0.1` as the address
    and takes the port from the service definition's `port` field. Note that
    allowing the application to listen on any non-loopback address may expose it
    externally and bypass Connect's access enforcement. It may be useful though
    to allow non-standard loopback addresses or where an alternative
    known-private IP is available for example when using internal networking
    between containers.

* <a name="local_connect_timeout_ms"></a><a href="#local_connect_timeout_ms">`local_connect_timeout_ms`</a>
  - The number of milliseconds the proxy will wait to establish a
    connection to the _local application_ before giving up. Defaults to `1000`
    or 1 second.

* <a name="handshake_timeout_ms"></a><a href="#handshake_timeout_ms">`handshake_timeout_ms`</a>
  - The number of milliseconds the proxy will wait for _incoming_ mTLS
    connections to complete the TLS handshake. Defaults to `10000` or 10
    seconds.

* <a name="upstreams"></a><a href="#upstreams">`upstreams`</a>
  - An array of upstream definitions for remote services that the proxied
    application needs to make outgoing connections to. Each definition has the
    following fields:
    * <a name="destination_name"></a><a href="#destination_name">`destination_name`</a>
      - [required] The name of the service or prepared query to route connect
        to.
    * <a name="local_bind_port"></a><a href="#local_bind_port">`local_bind_port`</a>
      - [required] The port to bind a local listener to for the application to
        make outbound connections to this upstream.
    * <a name="local_bind_address"></a><a href="#local_bind_address">`local_bind_address`</a>
      - The address to bind a local listener to for the application to make
      outbound connections to this upstream.
    * <a name="destination_type"></a><a href="#destination_type">`destination_type`</a>
      - Either `service` or `upstream`. The type of discovery query to use to
        find an instance to connect to. Defaults to `service`.
    * <a name="destination_datacenter"></a><a href="#destination_datacenter">`destination_datacenter`</a>
      - The datacenter to issue the discovery query too. Defaults to the local
        datacenter.
    * <a name="connect_timeout_ms"></a><a href="#connect_timeout_ms">`connect_timeout_ms`</a>
      - The number of milliseconds the proxy will wait to establish a connection
        to and complete TLS handshake with the _remote_ application or proxy.
        Defaults to `10000` or 10 seconds.