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AWS Direct Connect
User Guide

Virtual Interfaces

You must create a virtual interface to begin using your AWS Direct Connect connection. You can create a private virtual interface to connect to your VPC, or you can create a public virtual interface to connect to AWS services that aren't in a VPC, such as Amazon S3 and Amazon Glacier. You can configure multiple virtual interfaces on a single AWS Direct Connect connection. For private virtual interfaces, you need one private virtual interface for each VPC to connect to from the AWS Direct Connect connection.

To connect to other AWS services using IPv6 addresses, check the service documentation to verify that IPv6 addressing is supported.

We advertise appropriate Amazon prefixes to you so you can reach either your VPCs or other AWS services. You can access all AWS prefixes in your region through this connection; for example, Amazon EC2, Amazon S3, and Amazon.com. You do not have access to non-Amazon prefixes or prefixes outside of your region. For the current list of IP prefixes advertised on AWS Direct Connect public connections, see the list in the AWS Direct Connect Discussion Forum.

Note

We recommend that you use a firewall filter (based on the source/destination address of packets) to control traffic to and from some prefixes. If you're using a prefix filter (route map), ensure that it accepts prefixes with an exact match or longer. Prefixes advertised from AWS Direct Connect may be aggregated and may differ from the prefixes defined in your prefix filter.

To use your AWS Direct Connect connection with another AWS account, you can create a hosted virtual interface for that account. A hosted virtual interface works the same as a standard virtual interface and can connect to public resources or a VPC.

A sub-1G connection only supports one virtual interface.

Prerequisites for Virtual Interfaces

The following information is needed for a virtual interface:

  • VLAN: Each virtual interface must be tagged with a new, unused customer-provided tag (VLAN ID) that complies with the Ethernet 802.1Q standard. This tag is required for any traffic traversing the AWS Direct Connect connection. The number must be between 1 and 4094.

  • Peer IP addresses: The IP address ranges that are assigned to each end of the virtual interface for the BGP peering session. A virtual interface can support a BGP peering session for IPv4, IPv6, or one of each (dual-stack). You cannot create multiple BGP sessions for the same IP addressing family on the same virtual interface.

    • IPv4: For a public virtual interface, you must specify public IPv4 addresses (/30) that you own. For a private virtual interface, Amazon can generate private IPv4 addresses for you.

    • IPv6: Regardless of the type of virtual interface, Amazon automatically allocates you a /125 IPv6 CIDR. You cannot specify your own peer IPv6 addresses.

  • BGP information: A virtual interface must have a public or private Border Gateway Protocol (BGP) Autonomous System Number (ASN). If you are using a public ASN, you must own it. If you are using a private ASN, it must be in the 64512 to 65535 range. Autonomous System (AS) prepending does not work if you use a private ASN. You can provide your own MD5 BGP authentication key, or you can let Amazon generate one for you.

  • (Private virtual interface only) The virtual private gateway for your VPC. For more information, see Adding a Hardware Virtual Private Gateway to Your VPC in the Amazon VPC User Guide.

  • (Public virtual interface only) Public IPv4 routes or IPv6 routes that you will advertise over BGP. You must advertise at least one prefix using BGP, up to a maximum of 1,000 prefixes.

    • IPv4: The IPv4 CIDR must not overlap with another IPv4 CIDR announced via AWS Direct Connect. If you do not have public IPv4 addresses, open a ticket with AWS Support.

    • IPv6: Specify a prefix length of /64 or shorter.