traefik/docs/content/middlewares/maxconnection.md

# MaxConnection

Limiting the Number of Simultaneous Clients
{: .subtitle }

![MaxConnection](../assets/img/middleware/maxconnection.png)

To proactively prevent services from being overwhelmed with high load, a maximum connection limit can be applied.

## Configuration Examples

??? example "File -- Limiting to 10 simultaneous connections"

    ```toml
    [http.middlewares]
      [http.middlewares.test-maxconn.maxconn]
      amount = 10 
    ```

??? example "Docker -- Limiting to 10 simultaneous connections"

    ```yml
    a-container:
          image: a-container-image 
            labels:
              - "traefik.http.middlewares.test-maxconn.maxconn.amount=10"
    ```

## Configuration Options

### amount

The `amount` option defines the maximum amount of allowed simultaneous connections.
The middleware will return an `HTTP 429 Too Many Requests` if there are already `amount` requests in progress (based on the same `extractorfunc` strategy).

### extractorfunc

The `extractorfunc` defines the strategy used to categorize requests.

The possible values are:

- `request.host` categorizes requests based on the request host.
- `client.ip` categorizes requests based on the client ip.
- `request.header.ANY_HEADER` categorizes requests based on the provided `ANY_HEADER` value.