---
layout: api
page_title: Connect - Agent - HTTP API
description: >-
  The /agent/connect endpoints interact with agent-local service mesh
  operations.
---

# Connect - Agent HTTP API

The `/agent/connect` endpoints interact with
with agent-local [service mesh](/consul/docs/connect) operations.

These endpoints may mirror the [non-agent service mesh endpoints](/consul/api-docs/connect)
in some cases. Almost all agent-local service mesh endpoints perform local caching
to optimize performance of the mesh without having to make requests to the server.

## Authorize

-> **Note:** This endpoint will always treat intentions with `Permissions`
defined as _deny_ intentions during evaluation, as this endpoint is only suited
for networking layer 4 (e.g. TCP) integration.
For performance and reliability reasons it is desirable to implement intention
enforcement by listing [intentions that match the
destination](/consul/api-docs/connect/intentions#list-matching-intentions) and representing
them in the native configuration of the proxy itself (such as RBAC for Envoy).

This endpoint tests whether a connection attempt is authorized between
two services. This is the primary API that must be implemented by
[proxies](/consul/docs/connect/proxy) or
[native integrations](/consul/docs/automate/native)
that wish to integrate with the service mesh. Prior to calling this API, it is expected
that the client TLS certificate has been properly verified against the
current CA roots.

The implementation of this API uses locally cached data
and doesn't require any request forwarding to a server. Therefore, the
response typically occurs in microseconds to impose minimal overhead on the
connection attempt.

| Method | Path                       | Produces           |
| ------ | -------------------------- | ------------------ |
| `POST` | `/agent/connect/authorize` | `application/json` |

The table below shows this endpoint's support for
[blocking queries](/consul/api-docs/features/blocking),
[consistency modes](/consul/api-docs/features/consistency),
[agent caching](/consul/api-docs/features/caching), and
[required ACLs](/consul/api-docs/api-structure#authentication).

| Blocking Queries | Consistency Modes | Agent Caching        | ACL Required    |
| ---------------- | ----------------- | -------------------- | --------------- |
| `NO`             | `none`            | `background refresh` | `service:write` |

### Query Parameters

- `ns` `(string: "")` <EnterpriseAlert inline /> - Specifies the namespace of the target service.
  You can also [specify the namespace through other methods](#methods-to-specify-namespace).

### JSON Request Body Schema

- `Target` `(string: <required>)` - The name of the service that is being
  requested.

- `ClientCertURI` `(string: <required>)` - The unique identifier for the
  requesting client. This is currently the URI SAN from the TLS client
  certificate.

- `ClientCertSerial` `(string: <required>)` - The colon-hex-encoded serial
  number for the requesting client cert.

- `Namespace` `(string: "")` <EnterpriseAlert inline /> - Specifies the namespace of
  the target service. This field takes precedence over the `ns` query parameter,
  one of several [other methods to specify the namespace](#methods-to-specify-namespace).

### Sample Payload

```json
{
  "Target": "db",
  "ClientCertURI": "spiffe://dc1-7e567ac2-551d-463f-8497-f78972856fc1.consul/ns/default/dc/dc1/svc/web",
  "ClientCertSerial": "04:00:00:00:00:01:15:4b:5a:c3:94"
}
```

### Sample Request

```shell-session
$ curl \
   --request POST \
   --data @payload.json \
    http://127.0.0.1:8500/v1/agent/connect/authorize
```

### Sample Response

```json
{
  "Authorized": true,
  "Reason": "Matched intention: web => db (allow)"
}
```

## Certificate Authority (CA) Roots

This endpoint returns the trusted certificate authority (CA) root certificates.
This is used by [proxies](/consul/docs/connect/proxy) or
[native integrations](/consul/docs/automate/native) to verify served client
or server certificates are valid.

This is equivalent to the [non-Agent service mesh endpoint](/consul/api-docs/connect),
but the response of this request is cached locally at the agent. This allows
for very fast response times and for fail open behavior if the server is
unavailable. This endpoint should be used by proxies and native integrations.

| Method | Path                      | Produces           |
| ------ | ------------------------- | ------------------ |
| `GET`  | `/agent/connect/ca/roots` | `application/json` |

The table below shows this endpoint's support for
[blocking queries](/consul/api-docs/features/blocking),
[consistency modes](/consul/api-docs/features/consistency),
[agent caching](/consul/api-docs/features/caching), and
[required ACLs](/consul/api-docs/api-structure#authentication).

| Blocking Queries | Consistency Modes | Agent Caching        | ACL Required |
| ---------------- | ----------------- | -------------------- | ------------ |
| `YES`            | `all`             | `background refresh` | `none`       |

### Sample Request

```shell-session
$ curl \
   http://127.0.0.1:8500/v1/agent/connect/ca/roots
```

### Sample Response

```json
{
  "ActiveRootID": "15:bf:3a:7d:ff:ea:c1:8c:46:67:6c:db:b8:81:18:36:ad:e5:d0:c7",
  "Roots": [
    {
      "ID": "15:bf:3a:7d:ff:ea:c1:8c:46:67:6c:db:b8:81:18:36:ad:e5:d0:c7",
      "Name": "Consul CA Root Cert",
      "SerialNumber": 7,
      "SigningKeyID": "1f:91:ca:41:8f:ac:67:bf:59:c2:fa:4e:75:5c:d8:f0:55:de:be:75:b8:33:31:d5:24:b0:04:b3:e8:97:5b:7e",
      "ExternalTrustDomain": "a1499528-fbf6-df7b-05e5-ae81e1873fc4",
      "NotBefore": "2018-05-21T16:33:28Z",
      "NotAfter": "2028-05-18T16:33:28Z",
      "RootCert": "-----BEGIN CERTIFICATE-----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\nfs2hBxWIELGwTAIgLdO7RRw+z9nnxCIA6kNl//mIQb+PGItespiHZKAz74Q=\n-----END CERTIFICATE-----\n",
      "IntermediateCerts": null,
      "Active": true,
      "PrivateKeyType": "ec",
      "PrivateKeyBits": 256,
      "CreateIndex": 8,
      "ModifyIndex": 8
    }
  ]
}
```

## Service Leaf Certificate

This endpoint returns the leaf certificate representing a single service.
This certificate is used as a server certificate for accepting inbound
connections and is also used as the client certificate for establishing
outbound connections to other services.

The agent generates a CSR locally and calls the
[CA sign API](/consul/api-docs/connect/ca) to sign it. The resulting certificate
is cached and returned by this API until it is near expiry or the root
certificates change.

Non blocking queries to this endpoint will always check that the leaf certificate is not expired
and that the root certificates have not changed. Otherwise, a new leaf certificate is generated.

This API supports blocking queries. The blocking query will block until 
a new certificate is necessary (because the existing certificate will expire, is expired, 
or the root certificate is being rotated), or until the query timeout is reached. The current
query timeout is set to 10 minutes. This blocking behavior allows clients to
wait for certificate rotations.

| Method | Path                              | Produces           |
| ------ | --------------------------------- | ------------------ |
| `GET`  | `/agent/connect/ca/leaf/:service` | `application/json` |

The table below shows this endpoint's support for
[blocking queries](/consul/api-docs/features/blocking),
[consistency modes](/consul/api-docs/features/consistency),
[agent caching](/consul/api-docs/features/caching), and
[required ACLs](/consul/api-docs/api-structure#authentication).

| Blocking Queries | Consistency Modes | Agent Caching        | ACL Required    |
| ---------------- | ----------------- | -------------------- | --------------- |
| `YES`            | `all`             | `background refresh` | `service:write` |

### Path Parameters

- `service` `(string: <required>)` - The name of the service for the leaf certificate.
  The service does not need to exist in the catalog, but the proper ACL permissions must be available.

### Query Parameters

- `ns` `(string: "")` <EnterpriseAlert inline /> - Specifies the namespace of the leaf certificate you request.
  You can also [specify the namespace through other methods](#methods-to-specify-namespace).

### Sample Request

```shell-session
$ curl \
   http://127.0.0.1:8500/v1/agent/connect/ca/leaf/web
```

### Sample Response

```json
{
  "SerialNumber": "08",
  "CertPEM": "-----BEGIN CERTIFICATE-----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\nOM/X3Yc1xb/qJiiEVzXcaz3oVFULOzrNAwk=\n-----END CERTIFICATE-----\n",
  "PrivateKeyPEM": "-----BEGIN EC PRIVATE KEY-----\nMHcCAQEEIAOGglbwY8HdD3LFX6Bc94co2pzeFTto8ebWoML5E+QfoAoGCCqGSM49\nAwEHoUQDQgAEl0upEp3VJHJwU4Vx4wc4FkpBbwcc7yNnkLx1GzAP4jBN3+i0k+Jo\n+tXMY4CLgyxoRSAMx6a83WOLLAe3cgjTyQ==\n-----END EC PRIVATE KEY-----\n",
  "Service": "web",
  "ServiceURI": "spiffe://11111111-2222-3333-4444-555555555555.consul/ns/default/dc/dc1/svc/web",
  "ValidAfter": "2018-05-21T16:33:28Z",
  "ValidBefore": "2018-05-24T16:33:28Z",
  "Namespace": "default",
  "CreateIndex": 5,
  "ModifyIndex": 5
}
```

- `SerialNumber` `string` - Monotonically increasing 64-bit serial number
  representing all certificates issued by this Consul cluster.

- `CertPEM` `(string)` - The PEM-encoded certificate.

- `PrivateKeyPEM` `(string)` - The PEM-encoded private key for this certificate.

- `Service` `(string)` - The name of the service that this certificate identifies.

- `ServiceURI` `(string)` - The URI SAN for this service.

- `ValidAfter` `(string)` - The time after which the certificate is valid.
  Used with `ValidBefore` this can determine the validity period of the certificate.

- `ValidBefore` `(string)` - The time before which the certificate is valid.
  Used with `ValidAfter` this can determine the validity period of the certificate.

## Methods to specify namespace <EnterpriseAlert inline />

Local agent service mesh endpoints
support several methods for specifying the namespace of resources
with the following order of precedence:
1. `Namespace` field of the JSON request body -
  only applies to the [register](#register-check) endpoint
1. `ns` query parameter
1. `X-Consul-Namespace` request header
1. Namespace is inherited from the namespace of the request's ACL token (if any)
1. The `default` namespace
