Thomas Eizinger 0008539b65 refactor(connlib): use dedicated UDP DNS client (#10850)
By default, DNS queries are sent over UDP by most systems. UDP is an
easy to understand protocol because each packet stands by itself and at
least as far as UDP is concerned, the payload is contained within a
single packet.

In Firezone, we receive all DNS traffic on the TUN device as IP packets.
Processing the UDP packets is trivial as each query is contained within
a single IP packet. For TCP, we first need to assemble the TCP stream
before we can read the entire query.

In case a DNS query is not for a Firezone DNS resource, we want to
forward it to the specified upstream resolver, either directly from the
system or - in case the specified upstream resolver is an IP resource -
through the tunnel as an IP packet. Specifically, the forwarding of UDP
DNS packets through the tunnel currently happens like this:

IP packet -> read UDP payload -> parse DNS query -> mangle original
destination IP to new upstream -> send through tunnel

For TCP DNS queries, it is not quite as easy as we have to decode the
incoming TCP stream first before we can parse the DNS query. Thus, when
we want to then forward the query, we need to open our own TCP stream to
the upstream resolver and encode the DNS query onto that stream, sending
each IP packet from the TCP client through the tunnel.

The difference in these designs makes several code paths in connlib hard
to follow.

Therefore - and despite the simplicity of DNS over UDP - we already
created our own "Layer 3 UDP DNS"-client. This PR now integrates this
client into the tunnel. Using this new client, we can simplify the
processing of UDP DNS queries because we never have to "go back" to the
original IP packet. Instead, when a DNS query needs to be forwarded to
an usptream resolver through the tunnel, we simply tell the Layer 3 UDP
DNS client to make a new DNS query. The processing of the resulting IP
packet then happens in a different place, right next to where we also
process the IP packets of the TCP DNS client.

That simplifications unlocks further refactorings where we now only
process DNS queries in a single place and the transport we received it
over is a simple function parameter with the control flow for both of
them being identical.

Related: #4668
2025-11-11 03:53:25 +00:00

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A modern alternative to legacy VPNs.


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Overview

Firezone is an open source platform to securely manage remote access for any-sized organization. Unlike most VPNs, Firezone takes a granular, least-privileged approach to access management with group-based policies that control access to individual applications, entire subnets, and everything in between.

architecture

Features

Firezone is:

  • Fast: Built on WireGuard® to be 3-4 times faster than OpenVPN.
  • Scalable: Deploy two or more gateways for automatic load balancing and failover.
  • Private: Peer-to-peer, end-to-end encrypted tunnels prevent packets from routing through our infrastructure.
  • Secure: Zero attack surface thanks to Firezone's holepunching tech which establishes tunnels on-the-fly at the time of access.
  • Open: Our entire product is open-source, allowing anyone to audit the codebase.
  • Flexible: Authenticate users via email, Google Workspace, Okta, Entra ID, or OIDC and sync users and groups automatically.
  • Simple: Deploy gateways and configure access in minutes with a snappy admin UI.

Firezone is not:

  • A tool for creating bi-directional mesh networks
  • A full-featured router or firewall
  • An IPSec or OpenVPN server

Contents of this repository

This is a monorepo containing the full Firezone product, marketing website, and product documentation, organized as follows:

Quickstart

The quickest way to get started with Firezone is to sign up for an account at https://app.firezone.dev/sign_up.

Once you've signed up, follow the instructions in the welcome email to get started.

Frequently asked questions (FAQ)

Can I self-host Firezone?

Our license won't stop you from self-hosting the entire Firezone product top to bottom, but our internal APIs are changing rapidly so we can't meaningfully support self-hosting Firezone in production at this time.

If you're feeling especially adventurous and want to self-host Firezone for educational or hobby purposes, follow the instructions to spin up a local development environment in CONTRIBUTING.md.

The latest published clients (on App Stores and on releases) are only guaranteed to work with the managed version of Firezone and may not work with a self-hosted portal built from this repository. This is because Apple and Google can sometimes delay updates to their app stores, and so the latest published version may not be compatible with the tip of main from this repository.

Therefore, if you're experimenting with self-hosting Firezone, you will probably want to use clients you build and distribute yourself as well.

See the READMEs in the following directories for more information on building each client:

How long will 0.7 be supported until?

Firezone 0.7 is currently end-of-life and has stopped receiving updates as of January 31st, 2024. It will continue to be available indefinitely from the legacy branch of this repo under the Apache 2.0 license.

How much does it cost?

We offer flexible per-seat monthly and annual plans for the cloud-managed version of Firezone, with optional invoicing for larger organizations. See our pricing page for more details.

Those experimenting with self-hosting can use Firezone for free without feature or seat limitations, but we can't provide support for self-hosted installations at this time.

Documentation

Additional documentation on general usage, troubleshooting, and configuration can be found at https://www.firezone.dev/kb.

Get Help

If you're looking for help installing, configuring, or using Firezone, check our community support options:

  1. Discussion Forums: Ask questions, report bugs, and suggest features.
  2. Join our Discord Server: Join live discussions, meet other users, and chat with the Firezone team.
  3. Open a PR: Contribute a bugfix or make a contribution to Firezone.

If you need help deploying or maintaining Firezone for your business, consider contacting our sales team to speak with a Firezone expert.

See all support options on our main support page.

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Developing and Contributing

See CONTRIBUTING.md.

Security

See SECURITY.md.

License

Portions of this software are licensed as follows:

  • All content residing under the "elixir/" directory of this repository, if that directory exists, is licensed under the "Elastic License 2.0" license defined in "elixir/LICENSE".
  • All third party components incorporated into the Firezone Software are licensed under the original license provided by the owner of the applicable component.
  • Content outside of the above mentioned directories or restrictions above is available under the "Apache 2.0 License" license as defined in "LICENSE".

WireGuard® is a registered trademark of Jason A. Donenfeld.

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