Windows Ec2 Instance often Doing DNS query with Public DNS Resolver.


Hi Team. My Windows ec2 instance instance is often communication with public DNS resolvers (google, azure, Cloudflare) instead of AWS VPC's DNS resolver. EC2 instance's Network settings are set to automatic (DHCP) and unchanged. can you please help me find why my ec2 is communication with public DNS resolvers (google, azure, Cloudflare).

findings source: Guard Duty Findings and VPC flow logs. note: This not my windows DNS Server

Regards, Jayaprakash M

2 Answers

I believe you asked the same question a week ago.

One thing comes to mind. Do you have Chrome installed??

As it can ignore the OS dns settings and use it’s own DNS servers.

profile picture
answered 10 months ago
  • yes system has Chrome installed.

  • Try disabling the Chrome's Built in DNS resolver. I believe its enabled by default and this could be causing your issues


Navigate to chrome://flags/ Look for #enable-async-dns Async DNS enabled/disabled displays whether the server uses its own asynchronous DNS resolver instead of the operating system's synchronous resolver. This is by default disabled normally so might not be the actual issue, it could be some other service/app installed that could be sending these queries too.

answered 10 months ago
  • can you please help me how to find the service/app doing this query.?

You are not logged in. Log in to post an answer.

A good answer clearly answers the question and provides constructive feedback and encourages professional growth in the question asker.

Guidelines for Answering Questions