AWS Client VPN is a managed client-based VPN service that enables secure access to AWS resources and resources in the on-premises network.
AWS VPN CloudHub
For more than one remote network e.g. multiple branch offices, multiple AWS hardware VPN connections can be created via the VPC to enable communication between these networks
AWS Software VPN
A VPN connection can be created to the remote network by using an EC2 instance in the VPC that’s running a third-party software VPN appliance.
AWS does not provide or maintain third-party software VPN appliances; however, there is a range of products provided by partners and open source communities.
AWS Direct Connect provides a dedicated private connection from a remote network to the VPC. Direct Connect can be combined with an AWS hardware VPN connection to create an IPsec-encrypted connection
Virtual Private Gateway – VGW
A virtual private gateway is the VPN concentrator on the AWS side of the VPN connection
Customer Gateway – CGW
A customer gateway is a physical device or software application on the customer side of the VPN connection.
When a VPN connection is created, the VPN tunnel comes up when traffic is generated from the remote side of the VPN connection.
By default, VGW is not the initiator; CGW must bring up the tunnels for the Site-to-Site VPN connection by generating traffic and initiating the Internet Key Exchange (IKE) negotiation process.
If the VPN connection experiences a period of idle time, usually 10 seconds, depending on the configuration, the tunnel may go down. To prevent this, a network monitoring tool to generate keepalive pings; for e.g. by using IP SLA.
A transit gateway is a transit hub that can be used to interconnect VPCs and on-premises networks.
A Site-to-Site VPN connection on a transit gateway can support either IPv4 traffic or IPv6 traffic inside the VPN tunnels.
A Site-to-Site VPN connection offers two VPN tunnels between a VGW or a transit gateway on the AWS side, and a CGW (which represents a VPN device) on the remote (on-premises) side.
VPN Routing Options
For a VPN connection, the route table for the subnets should be updated with the type of routing (static or dynamic) that you plan to use.
Route tables determine where network traffic is directed. Traffic destined for the VPN connections must be routed to the virtual private gateway.
The type of routing can depend on the make and model of the CGW device
If your device does not support BGP, specify static routing.
Using static routing, the routes (IP prefixes) can be specified that should be communicated to the virtual private gateway.
Devices that don’t support BGP may also perform health checks to assist failover to the second tunnel when needed.
BGP Dynamic Routing
If the VPN device supports Border Gateway Protocol (BGP), specify dynamic routing with the VPN connection.
When using a BGP device, static routes need not be specified to the VPN connection because the device uses BGP for auto-discovery and to advertise its routes to the virtual private gateway.
BGP-capable devices are recommended as the BGP protocol offers robust liveness detection checks that can assist failover to the second VPN tunnel if the first tunnel goes down.
Only IP prefixes known to the virtual private gateway, either through BGP advertisement or static route entry, can receive traffic from the VPC.
Virtual private gateway does not route any other traffic destined outside of the advertised BGP, static route entries, or its attached VPC CIDR.
VPN Route Priority
Longest prefix match applies.
If the prefixes are the same, then the VGW prioritizes routes as follows, from most preferred to least preferred:
BGP propagated routes from an AWS Direct Connect connection
Manually added static routes for a Site-to-Site VPN connection
BGP propagated routes from a Site-to-Site VPN connection
Prefix with the shortest AS PATH is preferred for matching prefixes where each Site-to-Site VPN connection uses BGP
Path with the lowest multi-exit discriminators (MEDs) value is preferred when the AS PATHs are the same length and if the first AS in the AS_SEQUENCE is the same across multiple paths.
supports only IPSec tunnel mode. Transport mode is currently not supported.
supports only one VGW can be attached to a VPC at a time.
does not support IPv6 traffic on a virtual private gateway.
does not support Path MTU Discovery.
does not support overlapping CIDR blocks for the networks. It is recommended to use non-overlapping CIDR blocks.
does not support transitive routing. So for traffic from on-premises to AWS via a virtual private gateway, it
does not support Internet connectivity through Internet Gateway
does not support Internet connectivity through NAT Gateway
does not support VPC Peered resources access through VPC Peering
However, Internet connectivity through NAT instance and VPC Interface Endpoint or PrivateLink services are accessible.
provides a bandwidth of 1.25 Gbps, currently.
AWS Site-to-Site VPN automatically sends notifications to the AWS AWS Health Dashboard
AWS Site-to-Site VPN is integrated with CloudWatch with the following metrics available
The state of the tunnels.
For static VPNs, 0 indicates DOWN and 1 indicates UP.
For BGP VPNs, 1 indicates ESTABLISHED and 0 is used for all other states.
For both types of VPNs, values between 0 and 1 indicate at least one tunnel is not UP.
The bytes received on the AWS side of the connection through the VPN tunnel from a customer gateway.
The bytes sent from the AWS side of the connection through the VPN tunnel to the customer gateway.
VPN Connection Redundancy
A VPN connection is used to connect the customer network to a VPC.
Each VPN connection has two tunnels to help ensure connectivity in case one of the VPN connections becomes unavailable, with each tunnel using a unique virtual private gateway public IP address.
Both tunnels should be configured for redundancy.
When one tunnel becomes unavailable, for e.g. down for maintenance, network traffic is automatically routed to the available tunnel for that specific VPN connection.
To protect against a loss of connectivity in case the customer gateway becomes unavailable, a second VPN connection can be set up to the VPC and virtual private gateway by using a second customer gateway.
Customer gateway IP address for the second VPN connection must be publicly accessible.
By using redundant VPN connections and CGWs, maintenance on one of the customer gateways can be performed while traffic continues to flow over the second customer gateway’s VPN connection.
Dynamically routed VPN connections using the Border Gateway Protocol (BGP) are recommended, if available, to exchange routing information between the customer gateways and the virtual private gateways.
Statically routed VPN connections require static routes for the network to be entered on the customer gateway side.
BGP-advertised and statically entered route information allow gateways on both sides to determine which tunnels are available and reroute traffic if a failure occurs.
Multiple Site-to-Site VPN Connections
VPC has an attached virtual private gateway, and the remote network includes a customer gateway, which must be configured to enable the
Routing must be set up so that any traffic from the VPC bound for the remote network is routed to the virtual private gateway.
Each VPN has two tunnels associated with it that can be configured on the customer router, as is not a single point of failure
Multiple VPN connections to a single VPC can be created, and a second CGW can be configured to create a redundant connection to the same external location or to create VPN connections to multiple geographic locations.
VPN CloudHub can be used to provide secure communication between multiple on-premises sites if you have multiple VPN connections
VPN CloudHub operates on a simple hub-and-spoke model using a Virtual Private gateway in a detached mode that can be used without a VPC.
Design is suitable for customers with multiple branch offices and existing
Internet connections who’d like to implement a convenient, potentially low-cost hub-and-spoke model for primary or backup connectivity between these remote offices
VPN CloudHub architecture with blue dashed lines indicates network
traffic between remote sites being routed over their VPN connections.
AWS VPN CloudHub requires a virtual private gateway with multiple customer gateways.
Each customer gateway must use a unique Border Gateway Protocol (BGP) Autonomous System Number (ASN)
Customer gateways advertise the appropriate routes (BGP prefixes) over their VPN connections.
Routing advertisements are received and re-advertised to each BGP peer, enabling each site to send data to and receive data from the other sites.
Routes for each spoke must have unique ASNs and the sites must not have overlapping IP ranges.
Each site can also send and receive data from the VPC as if they were using a standard VPN connection.
Sites that use AWS Direct Connect connections to the virtual private gateway can also be part of the AWS VPN CloudHub.
To configure the AWS VPN CloudHub,
multiple customer gateways can be created, each with the unique public IP address of the gateway and the ASN.
a VPN connection can be created from each customer gateway to a common virtual private gateway.
each VPN connection must advertise its specific BGP routes. This is done using the network statements in the VPN configuration files for the VPN connection.
Questions are collected from Internet and the answers are marked as per my knowledge and understanding (which might differ with yours).
AWS services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
AWS exam questions are not updated to keep up the pace with AWS updates, so even if the underlying feature has changed the question might not be updated
Open to further feedback, discussion and correction.
You have in total 5 offices, and the entire employee-related information is stored under AWS VPC instances. Now all the offices want to connect the instances in VPC using VPN. Which of the below help you to implement this?
you can have redundant customer gateways between your data center and your VPC
you can have multiple locations connected to the AWS VPN CloudHub
You have to define 5 different static IP addresses in route table.
1 and 2
1,2 and 3
You have in total of 15 offices, and the entire employee-related information is stored under AWS VPC instances. Now all the offices want to connect the instances in VPC using VPN. What problem do you see in this scenario?
You can not create more than 1 VPN connections with single VPC (Can be created)
You can not create more than 10 VPN connections with single VPC (soft limit can be extended)
When you create multiple VPN connections, the virtual private gateway can not sends network traffic to the appropriate VPN connection using statically assigned routes. (Can route the traffic to correct connection)
Statically assigned routes cannot be configured in case of more than 1 VPN with the virtual private gateway. (can be configured)
None of above
You have been asked to virtually extend two existing data centers into AWS to support a highly available application that depends on existing, on-premises resources located in multiple data centers and static content that is served from an Amazon Simple Storage Service (S3) bucket. Your design currently includes a dual-tunnel VPN connection between your CGW and VGW. Which component of your architecture represents a potential single point of failure that you should consider changing to make the solution more highly available?
Add another VGW in a different Availability Zone and create another dual-tunnel VPN connection.
Add another CGW in a different data center and create another dual-tunnel VPN connection. (Refer link)
Add a second VGW in a different Availability Zone, and a CGW in a different data center, and create another dual-tunnel.
No changes are necessary: the network architecture is currently highly available.
You are designing network connectivity for your fat client application. The application is designed for business travelers who must be able to connect to it from their hotel rooms, cafes, public Wi-Fi hotspots, and elsewhere on the Internet. You do not want to publish the application on the Internet. Which network design meets the above requirements while minimizing deployment and operational costs? [PROFESSIONAL]
Implement AWS Direct Connect, and create a private interface to your VPC. Create a public subnet and place your application servers in it. (High Cost and does not minimize deployment)
Implement Elastic Load Balancing with an SSL listener that terminates the back-end connection to the application. (Needs to be published to internet)
Configure an IPsec VPN connection, and provide the users with the configuration details. Create a public subnet in your VPC, and place your application servers in it. (Instances still in public subnet are internet accessible)
Configure an SSL VPN solution in a public subnet of your VPC, then install and configure SSL VPN client software on all user computers. Create a private subnet in your VPC and place your application servers in it. (Cost effective and can be in private subnet as well)
You are designing a connectivity solution between on-premises infrastructure and Amazon VPC Your server’s on-premises will De communicating with your VPC instances You will De establishing IPSec tunnels over the internet You will be using VPN gateways and terminating the IPsec tunnels on AWS-supported customer gateways. Which of the following objectives would you achieve by implementing an IPSec tunnel as outlined above? (Choose 4 answers) [PROFESSIONAL]
End-to-end protection of data in transit
End-to-end Identity authentication
Data encryption across the Internet
Protection of data in transit over the Internet
Peer identity authentication between VPN gateway and customer gateway
Data integrity protection across the Internet
A development team that is currently doing a nightly six-hour build which is lengthening over time on-premises with a large and mostly under utilized server would like to transition to a continuous integration model of development on AWS with multiple builds triggered within the same day. However, they are concerned about cost, security and how to integrate with existing on-premises applications such as their LDAP and email servers, which cannot move off-premises. The development environment needs a source code repository; a project management system with a MySQL database resources for performing the builds and a storage location for QA to pick up builds from. What AWS services combination would you recommend to meet the development team’s requirements? [PROFESSIONAL]
A Bastion host Amazon EC2 instance running a VPN server for access from on-premises, Amazon EC2 for the source code repository with attached Amazon EBS volumes, Amazon EC2 and Amazon RDS MySQL for the project management system, EIP for the source code repository and project management system, Amazon SQL for a build queue, An Amazon Auto Scaling group of Amazon EC2 instances for performing builds and Amazon Simple Email Service for sending the build output. (Bastion is not for VPN connectivity also SES should not be used)
An AWS Storage Gateway for connecting on-premises software applications with cloud-based storage securely, Amazon EC2 for the resource code repository with attached Amazon EBS volumes, Amazon EC2 and Amazon RDS MySQL for the project management system, EIPs for the source code repository and project management system, Amazon Simple Notification Service for a notification initiated build, An Auto Scaling group of Amazon EC2 instances for performing builds and Amazon S3 for the build output. (Storage Gateway does provide secure connectivity but still needs VPN. SNS alone cannot handle builds)
An AWS Storage Gateway for connecting on-premises software applications with cloud-based storage securely, Amazon EC2 for the resource code repository with attached Amazon EBS volumes, Amazon EC2 and Amazon RDS MySQL for the project management system, EIPs for the source code repository and project management system, Amazon SQS for a build queue, An Amazon Elastic Map Reduce (EMR) cluster of Amazon EC2 instances for performing builds and Amazon CloudFront for the build output. (Storage Gateway does not provide secure connectivity, still needs VPN. EMR is not ideal for performing builds as it needs normal EC2 instances)
A VPC with a VPN Gateway back to their on-premises servers, Amazon EC2 for the source-code repository with attached Amazon EBS volumes, Amazon EC2 and Amazon RDS MySQL for the project management system, EIPs for the source code repository and project management system, SQS for a build queue, An Auto Scaling group of EC2 instances for performing builds and S3 for the build output. (VPN gateway is required for secure connectivity. SQS for build queue and EC2 for builds)
VPC endpoint provides a private connection from VPC to supported AWS services and VPC endpoint services powered by PrivateLink without requiring an internet gateway, NAT device, VPN connection, or AWS Direct Connect connection.
Instances in the VPC do not require public IP addresses to communicate with resources in the service. Traffic between the VPC and the other service does not leave the Amazon network.
VPC Endpoints are virtual devices and are horizontally scaled, redundant, and highly available VPC components that allow communication between instances in the VPC and services without imposing availability risks or bandwidth constraints on the network traffic.
VPC Endpoints are of two types
Interface Endpoints – is an elastic network interface with a private IP address that serves as an entry point for traffic destined to supported services.
Gateway Endpoints – is a gateway that is a target for a specified route in your route table, used for traffic destined to a supported AWS service. Currently only Amazon S3 and DynamoDB.
provides private connectivity between VPCs, AWS services, and your on-premises networks without exposing your traffic to the public internet.
helps privately expose a service/application residing in one VPC (service provider) to other VPCs (consumer) within an AWS Region in a way that only consumer VPCs initiate connections to the service provider VPC.
With ALB as a target of NLB, ALB’s advanced routing capabilities can be combined with AWS PrivateLink.
enables networking connection between two VPCs to route traffic between them using private IPv4 addresses or IPv6 addresses
connections can be created between your own VPCs, or with a VPC in another AWS account.
enables full bidirectional connectivity between the VPCs
supports inter-region VPC peering connection
uses existing underlying AWS infrastructure
does not have a single point of failure for communication or a bandwidth bottleneck.
VPC Peering connections have limitations
cannot be used with Overlapping CIDR blocks
does not provide Transitive peering
does not support Edge to Edge routing through Gateway or private connection
is best used when resources in one VPC must communicate with resources in another VPC, the environment of both VPCs is controlled and secured, and the number of VPCs to be connected is less than 10
AWS VPN CloudHub allows you to securely communicate from one site to another using AWS Managed VPN or Direct Connect
AWS VPN CloudHub operates on a simple hub-and-spoke model that can be used with or without a VPC
AWS VPN CloudHub can be used if you have multiple branch offices and existing internet connections and would like to implement a convenient, potentially low cost hub-and-spoke model for primary or backup connectivity between these remote offices.
AWS VPN CloudHub leverages VPC virtual private gateway with multiple gateways, each using unique BGP autonomous system numbers (ASNs).
A transit VPC is a common strategy for connecting multiple, geographically disperse VPCs and remote networks in order to create a global network transit center.
A transit VPC simplifies network management and minimizes the number of connections required to connect multiple VPCs and remote networks
Transit VPC can be used to support important use cases
Private Networking – You can build a private network that spans two or more AWS Regions.
Shared Connectivity – Multiple VPCs can share connections to data centers, partner networks, and other clouds.
Cross-Account AWS Usage – The VPCs and the AWS resources within them can reside in multiple AWS accounts.
Transit VPC design helps implement more complex routing rules, such as network address translation between overlapping network ranges, or to add additional network-level packet filtering or inspection.
supports Transitive routing using the overlay VPN network — allowing for a simpler hub and spoke design. Can be used to provide shared services for VPC Endpoints, Direct Connect connection, etc.
supports network address translation between overlapping network ranges.
supports vendor functionality around advanced security (layer 7 firewall/Intrusion Prevention System (IPS)/Intrusion Detection System (IDS) ) using third-party software on EC2
leverages instance-based routing that increases costs while lowering availability and limiting the bandwidth.
Customers are responsible for managing the HA and redundancy of EC2 instances running the third-party vendor virtual appliance
AWS Direct Connect helps establish a dedicated private connection between an on-premises network and AWS.
Direct Connect can reduce network costs, increase bandwidth throughput, and provide a more consistent network experience than internet-based or VPN connections
Direct Connect uses industry-standard VLANs to access EC2 instances running within a VPC using private IP addresses
Direct Connect lets you establish
Dedicated Connection: A 1G, 10G, or 100G physical Ethernet connection associated with a single customer through AWS.
Hosted Connection: A 1G or 10G physical Ethernet connection that an AWS Direct Connect Partner provisions on behalf of a customer.
Direct Connect provides the following Virtual Interfaces
Private virtual interface – to access a VPC using private IP addresses.
Public virtual interface – to access all AWS public services using public IP addresses.
Transit virtual interface – to access one or more transit gateways associated with Direct Connect gateways.
Direct Connect connections are not redundant as each connection consists of a single dedicated connection between ports on your router and an Amazon router
Direct Connect High Availability can be configured using
Multiple Direct Connect connections
Back-up IPSec VPN connection
Direct Connect link aggregation group (LAG) is a logical interface that uses the Link Aggregation Control Protocol (LACP) to aggregate multiple connections at a single AWS Direct Connect endpoint, allowing you to treat them as a single, managed connection.
LAGs need the following
All connections in the LAG must use the same bandwidth.
A maximum of four connections in a LAG. Each connection in the LAG counts toward the overall connection limit for the Region.
All connections in the LAG must terminate at the same AWS Direct Connect endpoint.