How to Flush DNS Cache on Mac: A Guide for macOS Big Sur Users

When using Docker or Kubernetes locally, you may encounter issues with DNS resolution, especially after upgrading to macOS Big Sur. One common issue is that your containers may not respond correctly all the time, leading to frustration and wasted time. In this article, we will explore how to flush your DNS cache on a Mac and resolve any DNS-related issues.

Debugging DNS Issues

I have personally encountered similar issues with my containers after upgrading from Catalina to Big Sur. Despite debugging and trying various solutions, I found that the problem persisted until I flushed my DNS cache. The issue was intermittent, causing some containers to respond correctly while others failed.

Flushing DNS Cache on Mac

To flush your DNS cache on a Mac, you can use the Terminal app. Open Spotlight by pressing Command + Space and search for 'Terminal.' Type the following commands:

1. `sudo dscacheutil -flushcache`

2. `sudo killall -HUP mDNSResponder`

These two commands will clear your DNS cache and restart the mDNSResponder service, which is responsible for managing DNS on your Mac.

Additional Commands

For macOS Big Sur users, you can use the following additional command to flush your DNS cache:

`sudo killall -HUP mDNSResponder`

This command is similar to the previous one but specifically targets the mDNSResponder service.

In conclusion, flushing your DNS cache on a Mac is a simple process that requires only a few commands. By following these steps, you can resolve DNS-related issues and ensure that your containers respond correctly all the time. Whether you're using Docker or Kubernetes locally or simply experiencing DNS issues with your Mac, this guide will help you get back to work quickly.

Mac big sur flush dns