# Amazon EC2 service endpoints
<a name="ec2-endpoints"></a>

An endpoint is a URL that serves as an entry point for an Amazon web service. Amazon EC2 supports the following endpoint types:
+ [IPv4 endpoints](#ipv4)
+ [Dual-stack endpoints](#ipv6) (support both IPv4 and IPv6)
+ [ FIPS endpoints](https://docs.amazonaws.cn/general/latest/gr/rande.html#FIPS-endpoints)

When you make a request, you can specify the endpoint to use. If you do not specify an endpoint, the IPv4 endpoint is used by default. To use a different endpoint type, you must specify it in your request. For examples of how to do this, see [Specifying endpoints](#examples). For a table of available endpoints, see [Service endpoints by Region](#service-endpoints).

## IPv4 endpoints
<a name="ipv4"></a>

IPv4 endpoints support IPv4 traffic only. IPv4 endpoints are available for all Regions.

If you specify the general endpoint, `ec2.amazonaws.com`, we use the endpoint for `us-east-1`. To use a different Region, specify its associated endpoint. For example, if you specify `ec2.us-east-2.amazonaws.com` as the endpoint, we direct your request to the `us-east-2` endpoint. 

IPv4 endpoint names use the following naming convention: 
+ `service.region.amazonaws.com`

For example, the IPv4 endpoint name for the `eu-west-1` Region is `ec2.eu-west-1.amazonaws.com`.

## Dual-stack (IPv4 and IPv6) endpoints
<a name="ipv6"></a>

Dual-stack endpoints support both IPv4 and IPv6 traffic. When you make a request to a dual-stack endpoint, the endpoint URL resolves to an IPv6 or an IPv4 address, depending on the protocol used by your network and client.

Amazon EC2 supports only regional dual-stack endpoints, which means that you must specify the Region as part of the endpoint name. Dual-stack endpoint names use the following naming convention:
+ `ec2.region.api.aws`

For example, the dual-stack endpoint name for the `eu-west-1` Region is `ec2.eu-west-1.api.aws`.

## Service endpoints by Region
<a name="service-endpoints"></a>

The following are the service endpoints for Amazon EC2. For more information about Regions, see [Regions and Availability Zones](https://docs.amazonaws.cn/AWSEC2/latest/UserGuide/using-regions-availability-zones.html) in the *Amazon EC2 User Guide*.

[\[See the AWS documentation website for more details\]](http://docs.amazonaws.cn/en_us/ec2/latest/devguide/ec2-endpoints.html)

## Specifying endpoints
<a name="examples"></a>

This section provides some examples of how to specify an endpoint when making a request.

------
#### [ Amazon CLI ]

The following examples show how to specify an endpoint for the `us-east-2` Region using the Amazon CLI.
+ **Dual-stack**

  ```
  aws ec2 describe-regions --region us-east-2 --endpoint-url https://ec2.us-east-2.api.aws
  ```
+ **IPv4**

  ```
  aws ec2 describe-regions --region us-east-2 --endpoint-url https://ec2.us-east-2.amazonaws.com
  ```

------
#### [ Amazon SDK for Java 2.x ]

The following examples show how to specify an endpoint for the `us-east-2` Region using the Amazon SDK for Java 2.x.
+ **Dual-stack**

  ```
  Ec2Client client = Ec2Client.builder()
      .region(Region.US_EAST_2)
      .endpointOverride(URI.create("https://ec2.us-east-2.api.aws"))
      .build();
  ```
+ **IPv4**

  ```
  Ec2Client client = Ec2Client.builder()
      .region(Region.US_EAST_2)
      .endpointOverride(URI.create("https://ec2.us-east-2.amazonaws.com"))
      .build();
  ```

------
#### [ Amazon SDK for Java 1.x ]

The following examples show how to specify an endpoint for the `eu-west-1` Region using the Amazon SDK for Java 1.x.
+ **Dual-stack**

  ```
  AmazonEC2 s3 = AmazonEC2ClientBuilder.standard()
       .withEndpointConfiguration(new EndpointConfiguration(
            "https://ec2.eu-west-1.api.aws",
            "eu-west-1"))
       .build();
  ```
+ **IPv4**

  ```
  AmazonEC2 s3 = AmazonEC2ClientBuilder.standard()
       .withEndpointConfiguration(new EndpointConfiguration(
            "https://ec2.eu-west-1.amazonaws.com",
            "eu-west-1"))
       .build();
  ```

------
#### [ Amazon SDK for Go ]

The following examples show how to specify an endpoint for the `us-east-1` Region using the Amazon SDK for Go.
+ **Dual-stack**

  ```
  sess := session.Must(session.NewSession())
  svc := ec2.New(sess, &aws.Config{
      Region: aws.String(endpoints.UsEast1RegionID),
      Endpoint: aws.String("https://ec2.us-east-1.api.aws")
  })
  ```
+ **IPv4**

  ```
  sess := session.Must(session.NewSession())
  svc := ec2.New(sess, &aws.Config{
      Region: aws.String(endpoints.UsEast1RegionID),
      Endpoint: aws.String("https://ec2.us-east-1.amazonaws.com")
  })
  ```

------