AWS Direct Connect Troubleshooting: Virtual Interface Down Issue

AWS Direct Connect Troubleshooting

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Question

Your company has created an AWS Direct Connect connection.

A virtual private gateway is attached to a VPC.

Around 111 routes are being advertised from On-premises.

A private VIF is being created for the VPGW.

But the Virtual Interface is always showing as down.

What needs to be done to ensure the interface comes back up?

Answers

Explanations

Click on the arrows to vote for the correct answer

A. B. C. D.

Answer - B.

The main issue is that more than 100 routes are being advertised.

Hence the tunnel is not coming up.

All other options are incorrect because all of these refer to VPN connections.

For more information on troubleshooting AWS Direct Connect connections, please refer to the below URL.

https://docs.aws.amazon.com/directconnect/latest/UserGuide/Troubleshooting.html

When a Virtual Interface is down, it means that there is no network connectivity between the customer's on-premises network and the Amazon VPC. The following are possible reasons why a Virtual Interface may remain down:

  1. Incorrect configuration of the BGP session
  2. Incorrect configuration of IPsec VPN tunnels
  3. Routing issues
  4. Physical issues, such as a bad fiber optic cable

To resolve the issue and bring the Virtual Interface up, one needs to troubleshoot the possible causes. The following steps can be taken to resolve the issue:

  1. Check the BGP configuration: Ensure that the BGP peering is configured correctly, and the routing protocol is working as expected. Check the on-premises router and the Direct Connect router to ensure that they are configured with the correct BGP settings. Verify that the virtual private gateway (VPG) has the correct BGP settings and that the Direct Connect gateway is attached to the VPC.

  2. Check the IPsec VPN configuration: Ensure that the IPsec VPN tunnel is configured correctly. Check the on-premises router and the Direct Connect router to ensure that they are configured with the correct IPsec settings. Verify that the VPG has the correct IPsec settings.

  3. Check the routing tables: Ensure that the routing tables are configured correctly. Check the on-premises router and the Direct Connect router to ensure that they are advertising the correct routes. Verify that the VPG has the correct routing table.

  4. Check the physical connection: Check the physical connection between the on-premises router and the Direct Connect router. Verify that the fiber optic cable is not damaged and that it is properly connected to the routers.

Based on the information provided in the question, option B is a possible solution. When there are too many routes being advertised, it can overload the BGP peering and cause the Virtual Interface to go down. To resolve this issue, one needs to reduce the number of routes being advertised from the on-premises network.

Option A is not a valid solution because a VPN connection is not required for Direct Connect to work. However, it is possible to use Direct Connect and VPN together to provide redundancy and additional connectivity options.

Option C is not a valid solution because static routes are not used with Direct Connect. BGP is used to exchange routes between the on-premises network and the VPC.

Option D is not a valid solution because the IPsec configuration is not relevant to the Direct Connect Virtual Interface. The IPsec VPN tunnel is a separate connection and does not affect the Direct Connect Virtual Interface.

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