#Host VPC

The host VPC is where you configure the systems that your application will use to connect to your MongoDB Atlas cluster. AWS provides your account with a default VPC for your hosts You may need to modify the default VPC or create a new one to work alongside MongoDB Atlas.

MongoDB Atlas requires your host VPC to follow the RFC-1918 standard for creating private ranges. The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP address space for private internets:

10.0.0.0 - 10.255.255.255 (10/8 prefix)

172.16.0.0 - 172.31.255.255 (172.16/12 prefix)

192.168.0.0 - 192.168.255.255 (192.168/16 prefix)

Don't overlap your ranges!

The point of peering is to permit two private IP ranges to work in conjunction to keep your network traffic off the public internet. This will require you to use separate private IP ranges that do not conflict.

AWS standard states the following in their "Invalid VPC Peering" document: