Incompatibility between Cloudflare WARP client and Multipass + solution

Cloudflare WARP is a VPN-like tool for optimizing one’s Internet speed. A macOS user found it was not possible to activate connections on it (port 53 taken), and found a solution.

Note: This might be beyond Multipass’s means to do anything about it. It’s likely between Apple and Cloudflare. Writing here in the hopes that others can find the work-around if affected.

Steps to reproduce

  1. Have Multipass (mine is 1.14.0-RC1) installed.
  2. Start a VM (multipass start default).
  3. Try to activate 1.1.1.1 (Cloudflare WARP) client.

Cloudflare WARP reports that mdnsresponder process is sitting on the port 53 and preventing the activation. If port 53 is taken, it seems that Multipass falls back on the qemu driver.

Workaround

  1. Stop running Multipass VMs.
  2. Activate Cloudflare WARP now.
  3. Restart the VM instances.

@akauppi I moved your GitHub issue (#3639) and workaround here, hopefully it will be helpful to someone else as well. Thanks for contributing!