Limitations of VPC peering

When setting up a VPC peering connection, we need to be aware of the following limitations:

• It is not possible to peer VPC with overlapping IPv4 or IPv6 CIDR blocks.
• Transitive peering is not supported; for example, peering A to B and B to C does not establish a link between A and C.
• Unicast reverse path forwarding in VPC peering connections is not supported.
• Tagging a VPC peering connection is only applied in the account or region in which you create them.

Additionally, inter-region VPC peering connections have the following limitations:

• The peer VPC's security groups cannot be referenced in security groups that are created in the other VPC.
• DNS resolution of hostnames that have both public and private IPs will only resolve public IPs when queried from the peered VPC.
• Communication over IPv6 is not supported.
• Communication over ClassicLink for EC2-Classic instances is not supported.
• Jumbo frames are not supported across the inter-region VPC peering connection.