Tutorial / Cram Notes
Maintaining private access to custom services is a critical requirement for many businesses, especially those with strict data security and privacy concerns. AWS offers several services such as AWS PrivateLink and VPC Peering that enable private connectivity between AWS services, your AWS Virtual Private Cloud (VPC), and on-premises networks.
AWS PrivateLink
AWS PrivateLink provides a secure and scalable way to connect services across different VPCs, AWS accounts, or on-premises networks. It allows you to access services hosted in AWS in a private manner, using private IP connectivity and thus avoiding the use of the public internet, which significantly reduces the exposure to network attacks.
With AWS PrivateLink, you can create interface VPC endpoints for AWS services that don’t have a default endpoint within the VPC, like API Gateway, AWS KMS, or your own custom services hosted in another VPC. These endpoints provide reliable, scalable connectivity without requiring traffic to traverse a public network.
How to set up AWS PrivateLink for custom services:
- Create an endpoint service on the service provider side of the VPC that allows you to define an Elastic Network Interface (ENI) as the entry point for the traffic.
- Create an endpoint on the service consumer side which corresponds to the service that you want to consume privately.
- The service provider must accept the connection from the service consumer to establish the necessary permissions.
By using AWS PrivateLink, you can ensure that data shared with your custom services never travels over the public internet, thereby reducing the risk of interception or exposure.
VPC Peering
VPC Peering is another way of ensuring private connectivity between two VPCs in the same or different AWS accounts. It enables you to route traffic between the VPCs using private IP addresses, again without the need for the data to traverse the public internet.
Unlike AWS PrivateLink, VPC Peering allows full connectivity between the VPCs. All subnets in each VPC can communicate with all subnets in the peered VPC.
Key considerations when using VPC Peering:
- VPC Peering connections are one-to-one relationships between two VPCs. To connect more than two VPCs, you would need multiple peering connections.
- There is no support for transitive peering; if VPC A is connected to VPC B and VPC B is connected to VPC C, VPC A and VPC C cannot communicate with each other unless there’s a direct peering connection between them.
- VPCs cannot have overlapping CIDR blocks in order to establish a peering connection.
Configuring VPC Peering:
- The owner of the requester VPC sends a peering connection request to the owner of the accepter VPC.
- The accepter VPC can either accept or reject the request.
- Once accepted, both VPCs can update their route tables to allow traffic to flow between them.
Overall, VPC Peering is more suitable for scenarios where broad network connectivity is required between VPCs, whereas PrivateLink is more focused on accessing specific services in a privacy-centric manner.
Comparison
| Aspect | AWS PrivateLink | VPC Peering |
|---|---|---|
| Connectivity | Service-specific connectivity | Full VPC-to-VPC connectivity |
| Scalability | Managed scaling | Manual peering setup for each VPC |
| Traffic | Does not traverse the public net | Does not traverse the public net |
| IP Overlapping | Not an issue | Not allowed |
| Use Cases | Accessing particular services | General inter-VPC communication |
| Transitive Peering | Not applicable | Not supported directly |
By understanding the features and use cases of AWS PrivateLink and VPC Peering, you can make informed decisions about how to maintain private access to custom services, ensuring your AWS Certified Advanced Networking – Specialty (ANS-C01) knowledge is accurate and up-to-date.
Practice Test with Explanation
True or False: AWS PrivateLink allows you to access AWS services securely over the public Internet.
- True
- False
Answer: False
Explanation: AWS PrivateLink provides private connectivity between VPCs, AWS services, and your on-premises networks, without exposing your traffic to the public internet.
In a VPC peering connection, can instances in the peer VPCs communicate without restriction to all the CIDR blocks in the other VPC?
- True
- False
Answer: True
Explanation: Once a VPC peering connection is established, instances in either VPC can communicate with each other as if they were within the same network, provided that there are no overlapping CIDR blocks or firewall restrictions preventing the communication.
What is the main benefit of using AWS PrivateLink for service consumers?
- Reducing cost
- Lowering latency
- Increasing public internet bandwidth
- Secure, private connectivity to services
Answer: Secure, private connectivity to services
Explanation: The main benefit of AWS PrivateLink for service consumers is that it provides a secure and private pathway to access services hosted on AWS, eliminating the need to use the public internet.
True or False: VPC peering supports transitive peering relationships natively.
- True
- False
Answer: False
Explanation: VPC peering does not support transitive peering natively; if you have three VPCs (A, B, and C) with peering connections between A-B and B-C, VPC A cannot communicate with VPC C through VPC B unless otherwise manually configured through routes.
Which of the following are use cases for AWS PrivateLink? (Select TWO)
- Sharing data across different AWS accounts
- Broadcasting data over the public internet
- Securely accessing third-party services
- Bypassing internet service providers
- Connecting to on-premises data centers via Direct Connect
Answer: Sharing data across different AWS accounts, Securely accessing third-party services
Explanation: AWS PrivateLink allows secure access to services across different AWS accounts and third-party services without needing to use the public internet, which is beneficial for privacy and security reasons.
Can you change the owner of a VPC peering connection once it’s established?
- Yes
- No
Answer: No
Explanation: The ownership of a VPC peering connection cannot be changed after it’s established. If you require the peering connection to have a different owner, you must delete and recreate it under the desired account.
True or False: With AWS PrivateLink, you can control which VPC endpoints can invoke your Lambda functions.
- True
- False
Answer: True
Explanation: AWS PrivateLink allows you to use VPC endpoint policies to control access to your Lambda functions.
Which AWS service allows you to establish private connectivity between VPCs in different regions?
- AWS Direct Connect
- Amazon Route 53
- VPC Peering
- Amazon CloudFront
Answer: VPC Peering
Explanation: AWS supports inter-region VPC peering, which allows private connectivity between VPCs in different regions.
True or False: AWS PrivateLink traffic is subject to standard AWS data transfer charges.
- True
- False
Answer: True
Explanation: Traffic that flows through AWS PrivateLink is subject to AWS data transfer charges in accordance with the pricing policies.
What does an AWS PrivateLink endpoint service comprise of? (Select TWO)
- Network Load Balancer
- An internet gateway
- A VPC endpoint
- A virtual private gateway
- An Elastic IP address
Answer: Network Load Balancer, A VPC endpoint
Explanation: An AWS PrivateLink Endpoint Service is composed of a Network Load Balancer which fronts the service to which you are connecting and the VPC endpoint inside the customer’s VPC that connects securely to the service.
Interview Questions
What is AWS PrivateLink and how does it secure service access?
AWS PrivateLink allows AWS services and third-party services to be accessed securely by VPC resources through private IP addresses. It secures service access by ensuring data does not traverse the public internet, thus reducing the exposure to network threats.
Can you use AWS PrivateLink to privately connect to services hosted in another VPC? If so, how?
Yes, AWS PrivateLink can be used to connect to services hosted in another VPC by setting up interface VPC endpoints. These endpoints provide private connectivity between VPCs, allowing you to access services without using public IPs or requiring the traffic to go through the public internet.
How does VPC peering differ from AWS PrivateLink?
VPC peering allows direct network connectivity between two VPCs as if they are on the same network, whereas AWS PrivateLink provides private connectivity to services across different networks. PrivateLink is primarily used to securely access AWS services or SaaS applications, while VPC peering is for interconnecting VPCs.
What are the DNS considerations when using AWS PrivateLink?
When using AWS PrivateLink, you will receive a DNS hostname that resolves to the private IP addresses of the endpoint network interfaces within your VPC. You need to ensure that your VPC is set up to use the Amazon-provided DNS server or a DNS server that forwards to the Amazon DNS server in order to resolve these hostnames internally.
Is it possible to access a service via AWS PrivateLink from on-premises? If so, how?
Yes, it is possible to access a service via AWS PrivateLink from on-premises. This can be achieved by connecting your on-premises network to your VPC using AWS Direct Connect or a VPN, and then utilizing the AWS PrivateLink endpoints within the VPC.
What are the benefits of using VPC endpoints with PrivateLink over an Internet Gateway or NAT Gateway for accessing AWS services?
Using VPC endpoints with PrivateLink has several benefits compared to Internet Gateways or NAT Gateways, such as enhanced security by keeping traffic within the AWS network, lower data processing and transfer costs, and reduced latency since the traffic does not leave the AWS backbone.
How do you manage access permissions when using AWS PrivateLink?
Access permissions for AWS PrivateLink are managed through resource-based policies attached to the VPC endpoint, or service-based policies on the endpoint service. These policies help govern which principals (users, roles, or other accounts) can access the services through the PrivateLink connection.
Can you set up VPC peering between VPCs in different AWS accounts or regions? If so, describe the process.
Yes, you can set up VPC peering between VPCs in different accounts and regions. The process involves sending a peering request from one VPC to another, which then needs to be accepted. Cross-account VPC peering requires appropriate permissions for both accounts, and cross-region peering requires setting up the peering connection to specify the correct regions.
What is the impact on network performance when using VPC peering compared to Public IP or Internet Gateway for inter-VPC communications?
Network performance is generally better when using VPC peering compared to public IPs or Internet Gateways, as it allows direct network routing without traversing the public internet, thereby reducing latency and potential bandwidth bottlenecks.
Are there any data transfer charges associated with AWS PrivateLink?
Yes, data transfer charges apply when using AWS PrivateLink. The costs are for data processed through the PrivateLink endpoints and are determined by the amount of data transferred and the region.
Describe a situation where you would use VPC peering over AWS PrivateLink.
A situation where VPC peering would be preferred over AWS PrivateLink is when there is a need for broad, direct connectivity between two VPCs that share a substantial amount of resources and services, as opposed to limited access to specific services offered by PrivateLink.
What are some limitations you need to be aware of when establishing VPC peering connections?
Some limitations include non-transitive peering (cannot route traffic through a peering connection to reach another VPC that’s peered with the target VPC), overlapping IP address ranges (VPCs cannot have overlapping CIDRs), and a maximum number of active peering connections that you can have, which varies depending on the VPC size.
This blog post on maintaining private access through PrivateLink and VPC peering was incredibly helpful! Thanks for sharing.
I appreciate the detailed explanation on VPC peering. It clarified a lot of doubts I had. Kudos!
Can anyone elaborate on the best practices for securing PrivateLink endpoints?
Thanks for this post. Really appreciate the concise explanations!
The section on the cost implications of PrivateLink vs VPC peering was particularly useful. Great job!
In my experience, VPC peering is simpler to implement than PrivateLink. Anyone else feels the same?
Thanks for the post. It’s going to be very helpful for my ANS-C01 prep!
System performance is a consideration when choosing between PrivateLink and VPC peering. Thoughts?