> ## Documentation Index
> Fetch the complete documentation index at: https://help.decodo.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Advanced Parameters

> Free Proxies Advanced Parameter Specification to Control Your Connection

The simplest way to control your connection is by **port**: each of your 10 IPs has a dedicated port, `dc.decodo.com:10001` through `10010`. Connect to a port to use that IP.

For request-level control, Decodo also offers a backconnect endpoint that accepts parameters passed in the username field.

To specify proxy parameters in your request, use the **Username and password** authentication method.

***

## Available Parameters

| Parameter | Example Value | Description                                                                                                                                 |
| --------- | ------------- | ------------------------------------------------------------------------------------------------------------------------------------------- |
| `ip`      | -             | IP address. You can target an IP address from your free proxy IP list.                                                                      |
| `country` | `us`          | Country code. Please provide it in a two-symbol ISO format. Free Proxy IPs are located in the **USA**, so `us` is the only available value. |

***

## Application Support

### User:pass method

The backconnect entry node can also be used in various applications. In such a case, you will need to pass every parameter for your session alongside the username in the **username** field like this:

`user-username-country-country_code`

In the example above, `username` represents your proxy username, which you would need to get from the authentication field. In the `password` field, you only need to enter the proxy user’s password.

***

## cURL Examples

To use these commands, just replace `username` and `password` with your proxy user credentials and run them in your Terminal or Command Prompt.

##### Get an IP from a random location (with Free Proxies, the **only** available location is the **US**) with a rotating session

```shellscript cURL theme={null}
curl -U "username:password" -x "dc.decodo.com:10000" "https://ip.decodo.com/json?provider=IPinfo"
```

##### Get an IP from a specific location (in this example, the US) with a static session

```shellscript cURL theme={null}
curl -U "user-username-country-us:password" -x "dc.decodo.com:10001" "https://ip.decodo.com/json?provider=IPinfo"
```

##### Get a specific IP (in this example, the IP remains unspecified) with a static session

```shellscript cURL theme={null}
curl -U "user-username-ip-x.x.x.x:password" -x "dc.decodo.com:10001" "https://ip.decodo.com/json?provider=IPinfo"
```

<Note>
  When using any backconnect parameter, your username is also considered one of the parameters, therefore you need to add `user-` prefix before specifying your username, just like with all other parameters.
</Note>

***

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