teleport/docs/pages/reference/networking.mdx

---
title: Networking
description: This reference explains the networking requirements of a Teleport cluster, including its public address, ports, and support for HTTP CONNECT proxies.
---

A Teleport cluster is a distributed system that may comprise a number of
networks. On Teleport Enterprise (Cloud), for example, the Auth Service and
Proxy Service run in Teleport-managed infrastructure, while Teleport users
manage Agents and `tbot` instances.

This reference guide describes the networking requirements of a Teleport
cluster.

## Public address

<Tabs>
<TabItem scope={["oss", "enterprise"]} label="Self-Hosted">

All Teleport services (e.g., the Proxy Service, Auth Service, and agents) have an
optional `public_addr` property that you can modify in each service's
configuration file. The public address can take an IP or a DNS name. It can also
be a list of values:

```yaml
public_addr: ["service1.example.com", "service2.example.com"]
```

<Admonition
  type="warning"
  title="Note"
>
  Only a single Proxy Service `public_addr` should be configured. Attempting
  to have multiple addresses can result in redirects to the first listed address
  that may not be available to the client.
</Admonition>

Specifying a public address for a Teleport service may be useful in the
following use cases:

- You have multiple identical services, e.g., Proxy Service instances, behind a
  load balancer.
- You want Teleport to issue an SSH certificate for the service with additional
  principals, e.g., host names.
</TabItem>
<TabItem scope={["cloud", "team"]} label="Cloud-Hosted">

On Teleport Enterprise (Cloud) the Teleport Agent services always
connect using reverse tunnels so there is no need to set a public address for an Agent.

</TabItem>
</Tabs>

## HTTP CONNECT proxies

Some networks funnel all connections through a proxy server where they can be
audited and access control rules can be applied. For these scenarios, Teleport
supports HTTP CONNECT tunneling. HTTP CONNECT applies to:

- `tsh` in all cases.
- Teleport services, such as the SSH Service and Database Service, that dial back to the Teleport Proxy Service.

To use HTTP CONNECT tunneling, set the `HTTPS_PROXY` and `HTTP_PROXY`
environment variables when running Teleport. You can also optionally set the
`NO_PROXY` environment variable to avoid use of the proxy when accessing
specified hosts/netmasks/ports.

By default, Teleport installations based on package managers (such as `apt` and
`yum`) configure the `teleport` systemd unit to read environment variables from
the file `/etc/default/teleport` by using the `EnvironmentFile` field:

```ini
(!/examples/systemd/teleport.service!)
```

To configure HTTP CONNECT tunneling, you can assign these environment variables
within `/etc/default/teleport` on machines that run Teleport binaries. Use the
following example, replacing `proxy.example.com` with the address of your proxy:

```
HTTP_PROXY=http://proxy.example.com:8080/
HTTPS_PROXY=http://proxy.example.com:8080/
NO_PROXY=localhost,127.0.0.1,192.168.0.0/16,172.16.0.0/12,10.0.0.0/8
```

When Teleport builds and establishes the reverse tunnel to the main cluster, it will funnel all traffic through the proxy. Specifically, if using the default configuration, Teleport will tunnel ports `3024` (SSH, reverse tunnel) and `3080` (HTTPS, establishing trust) through the proxy.
If you don't want to proxy some of this traffic (for example, proxying HTTPS but not SSH), assign `NO_PROXY` to the address of the Teleport Proxy Service endpoint you want to exclude from HTTP_CONNECT tunneling in `host:port` format.

For example, you can modify the environment file at `/etc/default/teleport` on
each machine that runs a Teleport binary to resemble the following:

```
HTTP_PROXY=http://httpproxy.example.com:8080/
HTTPS_PROXY=http://httpproxy.example.com:8080/
NO_PROXY=teleportproxy.example.com:3024
```

The value of `HTTPS_PROXY` or `HTTP_PROXY` should be in the format
`scheme://[user[:password]@]host:port` where scheme is either `https` or `http` . If the value is
`host:port` , Teleport will prepend `http` .

<Admonition
  type="warning"
  title="Note"
>
  `localhost` and `127.0.0.1` are invalid values for the proxy host. If for some reason your proxy runs locally, you'll need to provide some other DNS name or a private IP address for it.
</Admonition>

<Admonition
  type="warning"
  title="Note"
>
  The Proxy Service also respects `HTTPS_PROXY` and `HTTP_PROXY` when connecting to a local Kubernetes cluster, which may not work. To fix this, add `kube.teleport.cluster.local` to `NO_PROXY`.
</Admonition>

## Ports

This section describes the ports you should open on your Teleport instances.

<Tabs>
<TabItem scope={["oss", "enterprise"]} label="Self-Hosted">

### Proxy Service ports

<Admonition
  type="tip"
  title="Note"
>

  To get a listing of the assigned ports for an instance of the Teleport Proxy
  Service, use the following command:

  ```code
  $ curl https://teleport.example.com:443/webapi/ping | jq
  ```

  Note that if `auth_service.proxy_listener_mode` is set to `multiplex` in your
  Teleport configuration, that means only a single port is used for
  multiple services through the Proxy.

</Admonition>

#### Ports with TLS routing

TLS routing is enabled by default. In this mode, all connections to a Teleport
service (e.g., the Teleport SSH Service or Kubernetes) are routed through the
Proxy Service's public web address.

Read more in our [TLS Routing](architecture/tls-routing.mdx) guide.

| Port | Downstream Service | Description |
| - | - | - |
| 443 | Proxy Service | In TLS Routing mode, the Proxy handles all protocols, including Web UI, HTTPS, Kubernetes, SSH, and all databases on a single port. |
| 3021 | Proxy Service | Port used by Teleport Proxy Service instances to dial agents in Proxy Peering mode. |

#### Ports without TLS routing

In some cases, administrators may want to use separate ports for different services.
In those cases, they can set up separate listeners in the config file.

| Port | Downstream Service | Description |
| - | - | - |
| 3021 | Proxy Service | Port used by Teleport Proxy Service instances to dial agents in Proxy Peering mode. |
| 3023 | All clients | SSH port clients connect to. The Proxy Service will forward this connection to port `3022` on the destination service or use a reverse tunnel connection. |
| 3024 | Auth Service | SSH port used to create reverse SSH tunnels from behind-firewall environments into a trusted Proxy Service instance. All Teleport services (e.g., the SSH Service and Database Service) connecting through the Proxy Service will use this port to form their reverse tunnel connections.|
| 3080 or 443 | Proxy Service | HTTPS connection to authenticate `tsh` users into the cluster. The same connection is used to serve a Web UI. |
| 3036 | Database Service | Traffic to MySQL databases.|
| 5432 | Database Service | Traffic to Postgres databases.|
| 27017 | Database Service | Traffic to MongoDB instances.|
| 6379 | Database Service | Traffic to Redis instances.|

### Auth Service ports

| Port | Downstream Service | Description |
| - | - | - |
| 3025 | All Teleport services | TLS port used by the Auth Service to serve its gRPC API to other Teleport services in a cluster.|

</TabItem>
<TabItem scope={["cloud", "team"]} label="Cloud-Hosted">

### Proxy Service ports

Cloud-hosted Teleport deployments allocate a different set of ports to each
tenant's Proxy Service. To see which ports are available for your Teleport
tenant, run a command similar to the following, replacing `example.teleport.sh`
with your tenant domain:

```code
$ curl https://example.teleport.sh/webapi/ping | jq '.proxy'
```

The output should resemble the following, including the unique ports assigned to
your tenant:

```json
{
  "kube": {
    "enabled": true,
    "listen_addr": "0.0.0.0:3080"
  },
  "ssh": {
    "listen_addr": "0.0.0.0:3080",
    "tunnel_listen_addr": "0.0.0.0:3080",
    "web_listen_addr": "0.0.0.0:3080",
    "public_addr": "example.teleport.sh:443",
    "dial_timeout": 30000000000
  },
  "db": {
    "postgres_listen_addr": "0.0.0.0:3080",
    "mysql_listen_addr": "0.0.0.0:3080"
  },
  "tls_routing_enabled": true
}
```

This output also indicates whether TLS routing is enabled for your tenant. When
TLS routing is enabled, connections to a Teleport service (e.g., the Teleport
SSH Service) are routed through the Proxy Service's public web address, rather
than through a port allocated to that service.

In this case, you can see that TLS routing is enabled, and that the Proxy
Service's public web address (`ssh.public_addr`) is `mytenant.teleport.sh:443`.

Read more in our [TLS Routing](architecture/tls-routing.mdx) guide.

</TabItem>
</Tabs>

### Agent ports

Teleport Agents dial the Teleport Proxy Service to establish a reverse tunnel.
Client traffic flows via the Proxy Service to the agent, and the agent forwards
traffic to resources in your infrastructure.

As a result, for Teleport processes running agents, e.g., instances of the SSH
Service, Kubernetes Service, and other services that protect resources in your
infrastructure, there is no need to open ports on the machines running the
agents to the public internet. 

### Direct connections to agents

If you run a self-hosted Teleport cluster, you can join an agent [directly to
the Teleport Auth Service](../enroll-resources/agents/join-token.mdx).
In this setup, certain Teleport services open their own listeners rather than
accepting connections via reverse tunnel. The Proxy Service connects to these
agent services by dialing them directly.

The table below describes the ports that each Teleport service opens for proxied
traffic:

| Port | Service | Traffic Type |
| - | - | - |
| 3022 | SSH Service | Incoming SSH connections.|
| 3026 | Kubernetes Service | HTTPS traffic to a Kubernetes API server.| 
| 3028 | Windows Desktop Service | Teleport Desktop Protocol traffic from Teleport clients.|

You can only access enrolled applications and desktops through the Teleport
Proxy Service. The Teleport Application Service and Teleport Database Service
use reverse tunnel connections through the Teleport Proxy Service and cannot
expose ports directly.

<Admonition type="important">
Direct auth joining is only supported for ssh and kube agents. Application, database, and other discovery-based features are not supported when joining auth directly.
</Admonition>