Remove the DNS over HTTPS (DoH) proxy feature built on CoreDNS due to
security vulnerabilities (GO-2025-3942, GO-2026-4289).
This removes:
- Standalone proxy-dns command (cloudflared proxy-dns)
- Tunnel subcommand (cloudflared tunnel proxy-dns)
- Proxy-dns flags for tunnel run (--proxy-dns, --proxy-dns-port, etc.)
- Config file resolver section support
- tunneldns/ package (CoreDNS-based implementation)
- Related component tests
BREAKING CHANGE: The proxy-dns feature is no longer available.
Users should migrate to alternative DNS over HTTPS solutions.
It might make sense for users to sometimes name their cloudflared
connectors to make identification easier than relying on hostnames that
TUN-7360 provides. This PR provides a new --label option to cloudflared
tunnel that a user could provide to give custom names to their
connectors.
João "Pisco" Fernandes
chungthuang
Sudarsan Reddy
João Oliveirinha
Devin Carr