---
isPrivate: true
title: Windows EC2 hostnames starting with EC2AMAZ-
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: Docs > Agent > Agent FAQ > Windows EC2 hostnames starting with EC2AMAZ-
---

# Windows EC2 hostnames starting with EC2AMAZ-

## Issue{% #issue %}

In the Datadog Agent v6 and v7, the default Agent in-app hostname for UNIX platforms on EC2 is the `instance-id`. For Windows hosts, the default Agent in-app hostname is the operating system hostname that starts with `EC2AMAZ-`.

For v6.18.0+ and v7.18.0+, the Agent logs the following warning for Windows hosts on EC2 where the hostname starts with `EC2AMAZ-`:

```
You may want to use the EC2 instance-id for the in-app hostname. For more information: https://docs.datadoghq.com/ec2-use-win-prefix-detection
```

## Resolution{% #resolution %}

If you see the warning message above, your options are:

- Continue using the in-app hostname (do nothing)
- Use the instance-id by following the instructions below

### EC2 instance-id for Windows host on EC2{% #ec2-instance-id-for-windows-host-on-ec2 %}

For v6.15.0+ and v7.15.0+, the Agent supports the configuration option `ec2_use_windows_prefix_detection` (default: `false`). When set to `true`, the in-app hostname for a Windows EC2 host is the instance-id for:

- New hosts (enabling this option works immediately)
- Hosts already reporting to Datadog. After enabling, message [Datadog support](https://docs.datadoghq.com/help/) to change the in-app hostname to the EC2 instance-id.