# Amazon-managed prefix lists
<a name="working-with-aws-managed-prefix-lists"></a>

Amazon-managed prefix lists are sets of IP address ranges for Amazon services. These prefix lists are maintained by Amazon Web Services and provide a way to reference the IP addresses used by various Amazon offerings. This can be particularly useful when configuring security groups or other network-level controls within a VPC.

The prefix lists cover a wide range of Amazon services, including S3 and DynamoDB, and many others. By using the managed prefix lists, you can ensure that your network configurations are up-to-date and properly account for the IP addresses used by the Amazon services you depend on. This can help simplify networking tasks and reduce the administrative overhead of manually maintaining lists of IP addresses.

In addition to the practical benefits, using the managed prefix lists also aligns with Amazon security best practices. By relying on the authoritative IP address information provided by Amazon, you can minimize the risk of misconfiguration or unexpected connectivity issues. This can be especially important for mission-critical applications or workloads with strict compliance requirements.

**Topics**
+ [Available Amazon-managed prefix lists](#available-aws-managed-prefix-lists)
+ [Amazon-managed prefix list weight](#aws-managed-prefix-list-weights)
+ [Use an Amazon-managed prefix list](#use-aws-managed-prefix-list)

## Available Amazon-managed prefix lists
<a name="available-aws-managed-prefix-lists"></a>

The following services provide Amazon-managed prefix lists.

[\[See the AWS documentation website for more details\]](http://docs.amazonaws.cn/en_us/vpc/latest/userguide/working-with-aws-managed-prefix-lists.html)

**To view the Amazon-managed prefix lists using the console**

1. Open the Amazon VPC console at [https://console.amazonaws.cn/vpc/](https://console.amazonaws.cn/vpc/).

1. In the navigation pane, choose **Managed Prefix Lists**.

1. In the search field, add the **Owner ID: Amazon** filter.

**To view the Amazon-managed prefix lists using the Amazon CLI**  
Use the [describe-managed-prefix-lists](https://docs.amazonaws.cn/cli/latest/reference/ec2/describe-managed-prefix-lists.html) command as follows.

```
aws ec2 describe-managed-prefix-lists --filters Name=owner-id,Values=AWS
```

## Amazon-managed prefix list weight
<a name="aws-managed-prefix-list-weights"></a>

The weight of an Amazon-managed prefix list refers to the number of entries that it takes up in a resource.

For example, the weight of a Amazon CloudFront managed prefix list is 55. Here's how the this affects your Amazon VPC quotas:
+ **Security groups** – The [default quota](amazon-vpc-limits.md#vpc-limits-security-groups) is 60 rules, leaving room for only 5 additional rules in a security group. You can [request a quota increase](https://console.amazonaws.cn/servicequotas/home/services/vpc/quotas/L-0EA8095F) for this quota.
+ **Route tables** – The [default quota](amazon-vpc-limits.md#vpc-limits-route-tables) is 50 routes, so you must [request a quota increase](https://console.amazonaws.cn/servicequotas/home/services/vpc/quotas/L-93826ACB) before you can add the prefix list to a route table.

## Use an Amazon-managed prefix list
<a name="use-aws-managed-prefix-list"></a>

Amazon-managed prefix lists are created and maintained by Amazon and can be used by anyone with an Amazon account. You cannot create, modify, share, or delete an Amazon-managed prefix list.

As with customer-managed prefix lists, you can use Amazon-managed prefix lists with Amazon resources such as security groups and route tables. For more information, see [Optimize Amazon infrastructure management with prefix lists](managed-prefix-lists-referencing.md).