A company is migrating an application from on premises to AWS. The company will host the application on Amazon EC2 instances that are deployed in a…

The requirement is for Amazon EC2 instances within a VPC to resolve on-premises DNS names. This is known as outbound DNS resolution from the VPC's perspective. The correct AWS service for this is an Amazon Route 53 Resolver outbound endpoint. This endpoint, combined with forwarding rules, directs DNS queries for specific on-premises domains to the on-premises DNS servers.

For the DNS queries to reach the on-premises network, private network connectivity is required between the VPC and the on-premises data center. Given the temporary 3-month migration period, an AWS Site-to-Site VPN is the most suitable option as it can be configured relatively quickly and involves less overhead than AWS Direct Connect, thus meeting the "LEAST amount of configuration" requirement.

B: This option is incorrect because it includes an unnecessary inbound endpoint and suggests AWS Direct Connect, which is typically more complex and time-consuming to set up than a VPN for a short-term requirement.

C: This option is incorrect because an AWS Client VPN is for individual user connections, not for site-to-site network connectivity. It also specifies an inbound endpoint, which resolves queries from on-premises to AWS, the opposite of what is needed.

D: This option is incorrect because a public VIF is used for accessing public AWS services, not for private connectivity to a VPC. It also incorrectly specifies an inbound endpoint for an outbound query scenario.

1. AWS Documentation: Resolving DNS queries between VPCs and your network. "To forward DNS queries from your VPCs to your network, you create a Route 53 Resolver outbound endpoint... For DNS queries to be forwarded... there must be a network connection between your VPC and your network, such as a VPN connection or an AWS Direct Connect connection." (Source: AWS Documentation, Route 53 Developer Guide, "Resolving DNS queries between VPCs and your network").

2. AWS Documentation: What is AWS Site-to-Site VPN? "You can use AWS Site-to-Site VPN to establish a secure connection between your data center or branch office and your AWS cloud resources." This confirms VPN as a valid connectivity method. (Source: AWS Documentation, AWS Site-to-Site VPN User Guide, "What is AWS Site-to-Site VPN?").

3. AWS Documentation: Forwarding rules. "You create forwarding rules that specify the domain names for DNS queries that you want to forward from your VPCs to an on-premises DNS resolver. To use forwarding rules, you also need to create a Resolver outbound endpoint." (Source: AWS Documentation, Route 53 Developer Guide, "Managing forwarding rules").