# Environment Variables

LibreNMS allows certain settings to be set via the environment or
through the .env file.

## Database

Set the variables to connect to the database.  The default values are shown below.

```dotenv
DB_HOST=localhost
DB_PORT=3306
DB_DATABASE=librenms
DB_USERNAME=librenms
DB_PASSWORD=
DB_SOCKET=
```

## Trusted Reverse Proxies

A comma separated list of trusted reverse proxy IPs or CIDR.

The default value is '127.0.0.1', which only allows reverse proxies on the localhost.

These options should be avoided for security reasons.
`'*'` means trust any proxie
`'**'` means trust any proxy up the chain.

```dotenv
APP_TRUSTED_PROXIES=192.168.1.0/24,192.167.8.20
```

## Base url

Set the base url for generated urls.

This will be needed when using signed graph urls for alerting. It may
be needed when using reverse proxies combined with a subdirectory.

Generally, LibreNMS will make correct URLs (especially if you have set
up your proxy variables correctly)

```dotenv
APP_URL=http://librenms/
```

## User / Group

The user and group that LibreNMS should operate as.
Group will default to the same as the user if unset.

```dotenv
LIBRENMS_USER=librenms
LIBRENMS_GROUP=librenms
```

## Debug

Increases the amount of information shown when an error occurs.

> WARNING: This may leak information, do not leave enabled.

```dotenv
APP_DEBUG=true
```