How to Encrypt AWS Direct Connect Traffic with IPsec VPN
A company uses AWS Direct Connect to connect its on-premises network to a VPC. The security team wants to ensure that traffic between the on-premises network and the VPC is encrypted using IPSec. Which solution meets this requirement?
Quick Answer
The correct answer is to establish an IPsec VPN connection over the Direct Connect public virtual interface using a customer gateway and a virtual private gateway. This works because the public VIF provides access to AWS public services, allowing you to terminate an IPsec tunnel over that logical connection, which encrypts all traffic between your on-premises network and the VPC while still leveraging the private, low-latency Direct Connect link. On the ANS-C01 exam, this scenario tests your understanding that Direct Connect itself does not encrypt traffic—you must layer encryption on top, and the public VIF is the correct termination point for the VPN, not the private VIF. A common trap is assuming a private VIF inherently provides encryption or that you need a separate internet-based VPN; instead, remember that the IPsec tunnel rides over the existing Direct Connect public VIF. Memory tip: “Public VIF for the VPN lift.”
⚠ Common exam trap
A common mix-up: candidates assume a private virtual interface inherently provides encryption, but Direct Connect private VIFs are unencrypted by default, and IPSec must be explicitly layered over a public VIF or via a VPN appliance.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Establish an IPSec VPN connection over the Direct Connect public virtual interface using a customer gateway and a virtual private gateway.
It establishes an IPSec VPN tunnel over a Direct Connect public virtual interface (VIF), which encrypts traffic between the on-premises network and the VPC. The customer gateway and virtual private gateway create a site-to-site VPN connection that uses IPSec to secure all data traversing the Direct Connect link, meeting the encryption requirement without relying on physical-layer security.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Establish an IPSec VPN connection over the Direct Connect public virtual interface using a customer gateway and a virtual private gateway.
Why this is correct
This combination provides encrypted IPSec tunnels over the Direct Connect connection.
- ✗
Use a private virtual interface (VIF) on the Direct Connect connection and enable encryption at the physical layer.
Why it's wrong here
Direct Connect does not provide encryption at the physical layer; encryption is optional and must be implemented at a higher layer.
- ✗
Use VPC endpoints (Gateway Endpoints) for all traffic between on-premises and the VPC.
Why it's wrong here
VPC endpoints allow private access to AWS services but do not encrypt traffic between on-premises and the VPC.
- ✗
Attach the Direct Connect virtual interface to a Transit Gateway and enable multicast.
Why it's wrong here
Transit Gateway does not provide encryption; multicast is unrelated.
Quick reference
VPN Protocol Comparison
| Protocol | Port | Encryption | Authentication | Use Case |
|---|---|---|---|---|
| IKEv2 / IPsec | UDP 500 / 4500 | AES-256 | Certificates / PSK | Site-to-site & remote access |
| SSL / TLS VPN | TCP 443 | TLS 1.3 | Certificates / MFA | Clientless remote access |
| L2TP / IPsec | UDP 1701 | AES (IPsec) | PSK / Certificates | Legacy remote access |
| WireGuard | UDP 51820 | ChaCha20 | Public keys | Modern high-performance VPN |
| PPTP | TCP 1723 | MPPE (weak) | MS-CHAPv2 | Legacy — avoid in production |
PPTP is considered insecure. IKEv2/IPsec and SSL VPN are the current recommended options.
Go deeper
Related to this question
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Same concept, more angles
4 more ways this is tested on ANS-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company is using AWS Direct Connect to connect its on-premises network to AWS. The company wants to encrypt all traffic between its on-premises network and AWS. Which solution meets this requirement?
easy- A.Use a public virtual interface (VIF) and route traffic through a NAT gateway.
- ✓ B.Use a private VIF and establish an IPsec VPN tunnel over the Direct Connect connection.
- C.Use a private virtual interface (VIF) and enable encryption on the Direct Connect connection.
- D.Use a private VIF and enable TLS on all applications.
Why B: AWS Direct Connect does not natively encrypt traffic; it provides a private, dedicated network connection. To meet the encryption requirement, you can establish an IPsec VPN tunnel over the private VIF, which encrypts all traffic between the on-premises network and the VPC. This approach combines the low latency and reliability of Direct Connect with the security of IPsec encryption.
Variation 2. A company uses AWS Direct Connect to connect its on-premises network to AWS. The security team wants to encrypt all traffic traversing the Direct Connect link. Which solution should be used?
medium- A.Enable encryption on the Direct Connect virtual interface
- B.Use TLS on all applications that communicate across the link
- ✓ C.Establish an IPsec VPN tunnel over the Direct Connect link
- D.Use VPC endpoints for all AWS services accessed
Why C: An IPsec VPN tunnel over Direct Connect encrypts all traffic traversing the link, providing encryption while maintaining low latency. Option A is wrong because Direct Connect does not natively encrypt data; encryption must be added separately. Option B is wrong because TLS only protects application-layer traffic, not all traffic at the network level. Option D is wrong because VPC endpoints only protect traffic to specific AWS services, not all traffic across the Direct Connect link.
Variation 3. A company has a Direct Connect connection to AWS. They want to encrypt all traffic between their on-premises network and their VPC. Which solution meets this requirement?
hard- A.Use MACsec on the Direct Connect connection.
- ✓ B.Set up a VPN connection over the Direct Connect link using IPsec.
- C.Enable encryption on the Direct Connect virtual interface.
- D.Use TLS for all traffic between on-premises and AWS.
Why B: Direct Connect does not inherently encrypt traffic. To encrypt all traffic between on-premises and the VPC, you can establish an IPsec VPN tunnel over the Direct Connect link. This encrypts traffic at the network layer. Option A is incorrect: MACsec provides physical-layer encryption but is not supported on all Direct Connect connections and does not encrypt all traffic end-to-end. Option C is incorrect: Direct Connect virtual interfaces do not provide encryption. Option D is incorrect: TLS is an application-layer protocol; it would require individual applications to support it and does not encrypt all traffic at the network layer.
Variation 4. A company is using AWS Direct Connect to connect on-premises to AWS. The security team wants to encrypt all traffic traversing the Direct Connect link. Which TWO options can achieve this?
hard- ✓ A.Establish an IPsec VPN tunnel over the Direct Connect virtual interface
- ✓ B.Enable MACsec on the Direct Connect dedicated connection
- C.Use TLS on all applications
- D.Use VPC gateway endpoints for S3
- E.Rely on Direct Connect's physical security
Why A: You can establish an IPsec VPN tunnel over a Direct Connect virtual interface to encrypt traffic at Layer 3. Option B is correct because MACsec (802.1ae) provides encryption at Layer 2 for dedicated connections. Option C is incorrect because TLS only encrypts specific application traffic, not all traffic traversing the link. Option D is incorrect because VPC gateway endpoints are used for private connectivity to S3 and DynamoDB, but they do not encrypt data across the Direct Connect link itself. Option E is incorrect because physical security does not provide encryption of data in transit.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ANS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the ANS-C01 exam.