Nick Khyl 9741c1e846 control/controlknobs,net/dns,tailcfg: add a control knob that disables hosts file updates on Windows
In the absence of a better mechanism, writing unqualified hostnames to the hosts file may be required
for MagicDNS to work on some Windows environments, such as domain-joined machines. It can also
improve MagicDNS performance on non-domain joined devices when we are not the device's primary
DNS resolver.

At the same time, updating the hosts file can be slow and expensive, especially when it already contains
many entries, as was previously reported in #14327. It may also have negative side effects, such as interfering
with the system's DNS resolution policies.

Additionally, to fix #18712, we had to extend hosts file usage to domain-joined machines when we are not
the primary DNS resolver. For the reasons above, this change may introduce risk.

To allow customers to disable hosts file updates remotely without disabling MagicDNS entirely, whether on
domain-joined machines or not, this PR introduces the `disable-hosts-file-updates` node attribute.

Updates #18712
Updates #14327

Signed-off-by: Nick Khyl <nickk@tailscale.com>
2026-02-13 11:59:37 -06:00
2026-02-10 17:16:07 -08:00
2026-01-27 16:15:17 -08:00

Tailscale

https://tailscale.com

Private WireGuard® networks made easy

Overview

This repository contains the majority of Tailscale's open source code. Notably, it includes the tailscaled daemon and the tailscale CLI tool. The tailscaled daemon runs on Linux, Windows, macOS, and to varying degrees on FreeBSD and OpenBSD. The Tailscale iOS and Android apps use this repo's code, but this repo doesn't contain the mobile GUI code.

Other Tailscale repos of note:

For background on which parts of Tailscale are open source and why, see https://tailscale.com/opensource/.

Using

We serve packages for a variety of distros and platforms at https://pkgs.tailscale.com.

Other clients

The macOS, iOS, and Windows clients use the code in this repository but additionally include small GUI wrappers. The GUI wrappers on non-open source platforms are themselves not open source.

Building

We always require the latest Go release, currently Go 1.25. (While we build releases with our Go fork, its use is not required.)

go install tailscale.com/cmd/tailscale{,d}

If you're packaging Tailscale for distribution, use build_dist.sh instead, to burn commit IDs and version info into the binaries:

./build_dist.sh tailscale.com/cmd/tailscale
./build_dist.sh tailscale.com/cmd/tailscaled

If your distro has conventions that preclude the use of build_dist.sh, please do the equivalent of what it does in your distro's way, so that bug reports contain useful version information.

Bugs

Please file any issues about this code or the hosted service on the issue tracker.

Contributing

PRs welcome! But please file bugs. Commit messages should reference bugs.

We require Developer Certificate of Origin Signed-off-by lines in commits.

See commit-messages.md (or skim git log) for our commit message style.

About Us

Tailscale is primarily developed by the people at https://github.com/orgs/tailscale/people. For other contributors, see:

WireGuard is a registered trademark of Jason A. Donenfeld.

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