Why is my AWS VPN not resolving domain names via DNS?

After upgrading the AWS VPN Client to version 5.0, I noticed that my domain names mapped to internal VPC IP’s could no longer be resolved.

Context

• I’m connected to an AWS VPC via the AWS VPN Client
• When attempting to resolve a DNS record which points to a service running in the VPC, this fails to resolve
  e.g. api.digitalsuperglue.com.cloud -> 10.1.2.3
• I can successfully connect to the service using its VPC IP, therefore I know the VPN is and IP routing are working

Note: For this AWS VPN configuration, it does NOT have preset primary and secondary DNS servers.

Solution

I discovered that sometimes people run into DNS issues with the AWS VPN Client, when running a local network which is similar to what your AWS VPC is using. I’ve noticed a quick search can reveal others who have reported a similar issue.

One way to fix this is to add the Google DNS servers, to your AWS VPN Interface.
For Windows, I did the following:

1. Go to Control Panel -> Network and Internet -> Network Conenctions and find the AWS VPN Interface:

   
   
   

2. On the Networking tab, select the Internet Protocol Version 4 (TCP/IPv4) option and click on Properties:

   
   

3. On the General tab, click Use the following DNS server addresses radio button and enter 8.8.8.8 and 4.4.4.4 for the two DNS inputs:

   

   Adding the DNS servers manually worked for me, now when using the VPN Client it resolves the domain names as expected.