Firefox has begun the rollout of encrypted DNS over HTTPS (DoH) by default for US-based users. The rollout will continue over the next few weeks to confirm no major issues are discovered as this new protocol is enabled for Firefox's US-based users.
A little over two years ago, we began work to help update and secure one of the oldest parts of the internet, the Domain Name System (DNS). To put this change into context, we need to briefly describe how the system worked before DoH.
DNS is a database that links a human-friendly name, such as www.mozilla.org, to a computer-friendly series of numbers, called an IP address (e.g. 192.0.2.1). By performing a lookup in this database, your web browser is able to find websites on your
behalf. Because of how DNS was originally designed decades ago, browsers doing DNS lookups for websites -- even encrypted https:// sites -- had to perform these lookups without encryption. We described the impact of insecure DNS on our privacy:
Because there is no encryption, other devices along the way might collect (or even block or change) this data too. DNS lookups are sent to servers that can spy on your website browsing history without either informing you or
publishing a policy about what they do with that information.
At the creation of the internet, these kinds of threats to people's privacy and security were known, but not being exploited yet. Today, we know that unencrypted DNS is
not only vulnerable to spying but is being exploited, and so we are helping the internet to make the shift to more secure alternatives. We do this by performing DNS lookups in an encrypted HTTPS connection. This helps hide your browsing history from
attackers on the network, helps prevent data collection by third parties on the network that ties your computer to websites you visit.
We're enabling DoH by default only in the US. If you're outside of the US and would like to
enable DoH, you're welcome to do so by going to Settings, then General, then scroll down to Networking Settings and click the Settings button on the right. Here you can enable DNS over HTTPS by clicking, and a checkbox will appear. By default, this
change will send your encrypted DNS requests to Cloudflare.Users have the option to choose between two providers 204 Cloudflare and NextDNS -- both of which are trusted resolvers.
Mozilla has announced that NextDNS would be joining Cloudflare as the second DNS-over-HTTPS (DoH) provider inside Firefox.
The browser maker says NextDNS passed the conditions imposed by its Trusted Recursive Resolver (TRR) program. These conditions
include
limiting the data NextDNS collects from the DoH server used by Firefox users;
being transparent about the data they collect; and
promising not to censor, filter, or block DNS traffic unless specifically requested by law enforcement.
The new option will appear some time next year.
DNS-over-HTTPS, or DoH, is a new feature that was added to Firefox last year. When enabled, it encrypts DNS traffic coming in and out of the browser.DNS traffic is not only encrypted but also moved
from port 53 (for DNS traffic) to port 443 (for HTTPS traffic), effectively hiding DNS queries and replies inside the browser's normal stream of HTTPS content.
Windows will improve user privacy with DNS over HTTPS
Here in Windows Core Networking, we're interested in keeping your traffic as private as possible, as well as fast and reliable. While there are many ways we can and do approach
user privacy on the wire, today we'd like to talk about encrypted DNS. Why? Basically, because supporting encrypted DNS queries in Windows will close one of the last remaining plain-text domain name transmissions in common web traffic.
Providing encrypted DNS support without breaking existing Windows device admin configuration won't be easy. However, at Microsoft we believe that
"we have to treat privacy as a human right. We have to have end-to-end cybersecurity built into technology."
We also believe Windows adoption of encrypted DNS will help make the overall Internet ecosystem healthier.
There is an assumption by many that DNS encryption requires DNS centralization. This is only true if encrypted DNS adoption isn't universal. To keep the DNS decentralized, it will be important for client operating systems (such as Windows) and Internet
service providers alike to widely adopt encrypted DNS .
With the
decision made to build support for encrypted DNS, the next step is to figure out what kind of DNS encryption Windows will support and how it will be configured. Here are our team's guiding principles on making those decisions:
Windows DNS needs to be as private and functional as possible by default without the need for user or admin configuration because Windows DNS traffic represents a snapshot of the user's browsing history. To Windows users,
this means their experience will be made as private as possible by Windows out of the box. For Microsoft, this means we will look for opportunities to encrypt Windows DNS traffic without changing the configured DNS resolvers set by users and system
administrators.
Privacy-minded Windows users and administrators need to be guided to DNS settings even if they don't know what DNS is yet. Many users are interested in controlling their privacy and go looking for
privacy-centric settings such as app permissions to camera and location but may not be aware of or know about DNS settings or understand why they matter and may not look for them in the device settings.
Windows users and
administrators need to be able to improve their DNS configuration with as few simple actions as possible. We must ensure we don't require specialized knowledge or effort on the part of Windows users to benefit from encrypted DNS. Enterprise policies
and UI actions alike should be something you only have to do once rather than need to maintain.
Windows users and administrators need to explicitly allow fallback from encrypted DNS once configured. Once Windows has
been configured to use encrypted DNS, if it gets no other instructions from Windows users or administrators, it should assume falling back to unencrypted DNS is forbidden.
Based on these principles, we are making plans to adopt DNS over HTTPS (or DoH) in the Windows DNS client. As a platform, Windows Core Networking seeks
to enable users to use whatever protocols they need, so we're open to having other options such as DNS over TLS (DoT) in the future. For now, we're prioritizing DoH support as the most likely to provide immediate value to everyone. For example, DoH
allows us to reuse our existing HTTPS infrastructure.
...
Why announce our intentions in advance of DoH being available to Windows Insiders? With encrypted DNS gaining more attention, we felt it was
important to make our intentions clear as early as possible. We don't want our customers wondering if their trusted platform will adopt modern privacy standards or not.
An absurd thing is happening in the halls of Congress. Major ISPs such as Comcast, AT&T, and Verizon are banging on the doors of legislators to stop the deployment of DNS over HTTPS (DoH), a technology that will give users one of the biggest
upgrades to their Internet privacy and security since the proliferation of HTTPS . This is because DoH ensures that when you look up a website, your query to the DNS system is secure through encryption and can't be tracked, spoofed, or blocked.
But despite these benefits, ISPs have written dozens of congressional leaders about their concerns, and are handing out misleading materials invoking Google as the boogeyman. EFF, Consumer Reports, and National Consumers League wrote
this letter in response .
The reason the ISPs are fighting so hard is that DoH might undo their multi-million dollar political effort to take away user privacy. DoH isn't a Google technology--it's a standard, like HTTPS. They know
that. But what is frustrating is barely two years ago, these very same lobbyists, and these very same corporations, were meeting with congressional offices and asking them to undo federal privacy rules that protect some of the same data that encrypted
DNS allows users to hide.
ISPs Want to Protect an Illegitimate Market of Privacy Invasive Practices to "Compete" with Google's Privacy Invasive Practices, Congress Should Abolish Both
Congress shouldn't take its cues from these players on user privacy. The last time they did, Congress voted to take away users' rights . As long as DNS traffic remains exposed, ISPs can exploit our data the same way that Facebook and Google do. That's the subtext of this ISP effort. Comcast and its rivals are articulating a race to the bottom. ISPs will compete with Internet giants on who can invade user privacy more, then sell that to advertisers.
The major ISPs have also pointed out that centralization of DNS may not be great for user privacy in the long run. That's true, but that would not be an issue if everyone adopted DoH across the board. Meaning, the solution isn't
to just deny anyone a needed privacy upgrade. The solution is to create laws that abolish the corporate surveillance model that exists today for both Google and Comcast.
But that's not what the ISPs want Congress to do, because
they're ultimately on the same side as Google and other big Internet companies--they don't want us to have effective privacy laws to handle these issues. Congress should ignore the bad advice it's getting from both the major ISPs and Big Tech on consumer
privacy, and instead listen to the consumer and privacy groups.
EFF and consumer groups have been pleading with Congress to pass a real privacy law, which would give individuals a right to sue corporations that violate their
privacy, mandate opt-in consent for use of personal information, and allowing the states to take privacy law further, should the need arise . But many in Congress are still just listening to big companies, even holding Congressional hearings that only
invite industry and no privacy groups to "learn" what to do next. In fact the only reason we don't have a strong federal privacy law because corporations like Comcast and Google want Congress to simply delete state laws like California's CCPA
and Illinois's Biometric Protection Act while offering virtually nothing to users.
DNS over HTTPS Technology Advances More than Just Privacy, It Advances Human Rights and Internet Freedom
Missing
from the debate is the impact DoH has on Internet freedom and human rights in authoritarian regimes where the government runs the broadband access network. State-run ISPs in Venezuela , China , and Iran have relied on insecure DNS traffic to censor
content and target activists . Many of the tools governments like China and Iran rely on in order to censor content relies on exposed DNS traffic that DoH would eliminate. In other words, widespread adoption of encrypted DNS will shrink the censorship
toolbox of authoritarian regimes across the world. In other words the old tools of censorship will be bypassed if DoH is systematically adopted globally. So while the debate about DoH is centered on data privacy and advertising models domestically, U.S.
policymakers should recognize the big picture being that DoH can further American efforts to promote Internet freedom around the world. They should in fact be encouraging Google and the ISPs to offer encrypted DNS services and for them to quickly adopt
it, rather than listen to ISP's pleas to stop it outright.
For ISPs to retain the power to censor the Internet, DNS needs to remain leaky and exploitable. That's where opposition to DoH is coming from. And the oposition to DoH
today isn't much different from early opposition to the adoption of HTTP.
EFF believes this is the wrong vision for the Internet. We've believed, since our founding, that user empowerment should be the center focus. Let's try to
advance the human right of privacy on all fronts. Establishing encrypted DNS can greatly advance this mission - fighting against DoH is just working on behalf of the censors.
DNS over HTTPS (DoH) is an encrypted internet protocol that makes it more difficult for ISPs and government censors to block users from being able to access banned websites It also makes it more difficult for state snoopers like GCHQ to keep tabs on
users' internet browsing history.
Of course this protection from external interference also makes it much internet browsing more safe from the threat of scammers, identity thieves and malware.
Google were once considering introducing DoH for
its Chrome browser but have recently announced that they will not allow it to be used to bypass state censors.
Mozilla meanwhile have been a bit more reasonable about it and allow users to opt in to using DoH. Now Mozilla is considering using DoH
by default in the US, but still with the proviso of implementing DoH only if the user is not using parental control or maybe corporate website blocking.
Mozilla explains in a blog post:
What's next in making Encrypted
DNS-over-HTTPS the Default
By Selena Deckelmann,
In 2017, Mozilla began working on the DNS-over-HTTPS (DoH) protocol, and since
June 2018 we've been running experiments in Firefox to ensure the performance and user experience are great. We've also been surprised and excited by the more than 70,000 users who have already chosen on their own to explicitly enable DoH in Firefox
Release edition. We are close to releasing DoH in the USA, and we have a few updates to share.
After many experiments, we've demonstrated that we have a reliable service whose performance is good, that we can detect and mitigate
key deployment problems, and that most of our users will benefit from the greater protections of encrypted DNS traffic. We feel confident that enabling DoH by default is the right next step. When DoH is enabled, users will be notified and given the
opportunity to opt out.
Results of our Latest Experiment
Our latest DoH experiment was designed to help us determine how we could deploy DoH, honor enterprise configuration and respect user choice
about parental controls.
We had a few key learnings from the experiment.
We found that OpenDNS' parental controls and Google's safe-search feature were rarely configured by Firefox users in the USA. In total, 4.3% of users in the study used OpenDNS' parental controls or safe-search. Surprisingly, there
was little overlap between users of safe-search and OpenDNS' parental controls. As a result, we're reaching out to parental controls operators to find out more about why this might be happening.
We found 9.2% of users
triggered one of our split-horizon heuristics. The heuristics were triggered in two situations: when websites were accessed whose domains had non-public suffixes, and when domain lookups returned both public and private (RFC 1918) IP addresses. There was
also little overlap between users of our split-horizon heuristics, with only 1% of clients triggering both heuristics.
Moving Forward
Now that we have these results, we want to tell you about the approach we have settled on to address managed networks and parental controls. At a high level, our plan is to:
Respect user choice for opt-in parental controls and disable DoH if we detect them;
Respect enterprise configuration and disable DoH unless explicitly enabled by enterprise configuration; and
Fall back to operating system defaults for DNS when split horizon configuration or other DNS issues cause lookup failures.
We're planning to deploy DoH in "fallback" mode; that is, if domain name lookups using DoH fail or if our heuristics are triggered, Firefox will fall back and use the default operating system DNS. This means that for the
minority of users whose DNS lookups might fail because of split horizon configuration, Firefox will attempt to find the correct address through the operating system DNS.
In addition, Firefox already detects that parental controls
are enabled in the operating system, and if they are in effect, Firefox will disable DoH. Similarly, Firefox will detect whether enterprise policies have been set on the device and will disable DoH in those circumstances. If an enterprise policy
explicitly enables DoH, which we think would be awesome, we will also respect that. If you're a system administrator interested in how to configure enterprise policies, please find documentation here.
Options for Providers of
Parental Controls
We're also working with providers of parental controls, including ISPs, to add a canary domain to their blocklists. This helps us in situations where the parental controls operate on the network rather than
an individual computer. If Firefox determines that our canary domain is blocked, this will indicate that opt-in parental controls are in effect on the network, and Firefox will disable DoH automatically.
This canary domain is
intended for use in cases where users have opted in to parental controls. We plan to revisit the use of this heuristic over time, and we will be paying close attention to how the canary domain is adopted. If we find that it is being abused to disable DoH
in situations where users have not explicitly opted in, we will revisit our approach.
Plans for Enabling DoH Protections by Default
We plan to gradually roll out DoH in the USA starting in late
September. Our plan is to start slowly enabling DoH for a small percentage of users while monitoring for any issues before enabling for a larger audience. If this goes well, we will let you know when we're ready for 100% deployment.
Russell Haworth, CEO of Nominet, Britain's domain name authority has outlined the UK's stance on maintaining UK censorship and surveillance capabilities as the introduction of encrypted DNS over HTTPS (DoH) will make their job a bit more difficult.
The authorities' basic idea is that UK ISPs will provide their own servers for DNS over HTTPS so that they can still use this DNS traffic to block websites and keep a log of everyone's internet use. Browser companies will then be expected to enforce
using the governments preferred DoH server.
And Google duly announced that it will comply with this censorship request. Google Chrome will only allow DoH servers that are government or corporate approved.
Note that this decision is more
nuanced than just banning internet users from sidestepping state censors. It also applies to users being prevented from sidestepping corporate controls on company networks, perhaps a necessary commercial consideration that simply can't be ignored.
Russell Haworth, CEO of Nominet explains:
Firefox and Google Chrome -- the two biggest web browsers with a combined market share of over 70% -- are both looking to implement DoH in the coming months, alongside other operators. The big question now is how they implement it, who they offer to be
the resolvers, and what policies they use. The benefit offered by DoH is encryption, which prevents eavesdropping or interception of DNS communication. However, DoH raises a number of issues which deserve careful consideration as we move towards it.
Some of the internet safety and security measures that have been built over the years involve the DNS. Parental controls, for example, generally rely on the ISP blocking particular domains for their customers. The Internet Watch
Foundation (IWF) also ask ISPs to block certain domains because they are hosting child sexual abuse material. There may also be issues for law enforcement using DNS data to track criminals. In terms of cyber security, many organisations currently use the
DNS to secure their networks, by blocking domains known to contain malware. All of these measures could be impacted by the introduction of DoH.
Sitting above all of these is one question: Will users know any of this is happening?
It is important that people understand how and where their data is being used. It is crucial that DoH is not simply turned on by default and DNS traffic disappears off to a server somewhere without people understanding and signing up to the privacy
implications. This is the reason what we have produced a simple explainer and will be doing more to communicate about DoH in the coming weeks.
DoH can bring positive changes, but only if it is accompanied by understanding, informed consent, and attention to some key principles, as detailed below:
Informed user choice:
users will need to be educated on the way in which their data use is changing so they can give their informed consent to this new approach. We also need some clarity on who would see the data, who can access the data and under what
circumstances, how it is being protected and how long it will be available for.
Equal or better safety:
DoH disrupts and potentially breaks safety measures that have built
over many years. It must therefore be the responsibility of the browsers and DoH resolvers who implement DoH to take up these responsibilities. It will also be important for current protections to be maintained.
Local jurisdiction and governance:
Local DoH resolvers will be needed in individual countries to allow for application of local law, regulators and safety bodies (like the IWF). This is also important to encourage innovation globally, rather than
having just a handful of operators running a pivotal service. Indeed, the internet was designed to be highly distributed to improve its resilience.
Security:
Many
organisations use the DNS for security by keeping suspicious domains that could include malware out of networks. It will be important for DoH to allow enterprises to continue to use these methods -- at Nominet we are embracing this in a scalable and
secure way for the benefit of customers through our cyber security offering.
Change is a constant in our digital age, and I for one would not stand in the way of innovation and development. This new approach to
resolving requests could be a real improvement for our digital world, but it must be implemented carefully and with the full involvement of Government and law enforcement, as well as the wider internet governance community and the third sector.
A Google developer has outlined tentative short term plans for DoH in Chrome. It suggest that Chrome will only allow the selection of DoH servers that are equivalent to approved non encrypted servers.
This is a complex space and our short term plans won't necessarily solve or mitigate all these issues but are nevertheless steps in the right direction.
For the first milestone, we are considering an auto-upgrade approach. At a
high level, here is how this would work:
Chrome will have a small (i.e. non-exhaustive) table to map non-DoH DNS servers to their equivalent DoH DNS servers. Note: this table is not finalized yet.
Per this table, if the system's recursive
resolver is known to support DoH, Chrome will upgrade to the DoH version of that resolver. On some platforms, this may mean that where Chrome previously used the OS DNS resolution APIs, it now uses its own DNS implementation in order to implement DoH.
A group policy will be available so that Administrators can disable the feature as needed.
Ability to opt-out of the experiment via chrome://flags.
In other words, this would upgrade the protocol used for DNS resolution while keeping the user's DNS provider unchanged. It's also important to note that DNS over HTTPS does not preclude its operator from offering features such as
family-safe filtering.
At the moment when internet users want to view a page, they specify the page they want in the clear. ISPs can see the page requested and block it if the authorities don't like it. A new internet protocol has been launched that encrypts the specification
of the page requested so that ISPs can't tell what page is being requested, so can't block it.
This new DNS Over HTTPS protocol is already available in Firefox which also provides an uncensored and encrypted DNS server. Users simply have to change the
settings in about:config (being careful of the dragons of course)
Questions have been
raised in the House of Lords about the impact on the UK's ability to censor the internet.
House of Lords, 14th May 2019, Internet Encryption Question
Baroness Thornton Shadow Spokesperson (Health)
2:53 pm, 14th May 2019
To ask Her Majesty 's Government what assessment they have made of the deployment of the Internet Engineering Task Force 's new " DNS over HTTPS " protocol and its implications for the blocking
of content by internet service providers and the Internet Watch Foundation ; and what steps they intend to take in response.
Lord Ashton of Hyde The Parliamentary Under-Secretary of State for Digital, Culture, Media and Sport
My Lords, DCMS is working together with the National Cyber Security Centre to understand and resolve the implications of DNS over HTTPS , also referred to as DoH, for the blocking of content online. This involves liaising
across government and engaging with industry at all levels, operators, internet service providers, browser providers and pan-industry organisations to understand rollout options and influence the way ahead. The rollout of DoH is a complex commercial and
technical issue revolving around the global nature of the internet.
Baroness Thornton Shadow Spokesperson (Health)
My Lords, I thank the Minister for that Answer, and I apologise to the House for
this somewhat geeky Question. This Question concerns the danger posed to existing internet safety mechanisms by an encryption protocol that, if implemented, would render useless the family filters in millions of homes and the ability to track down
illegal content by organisations such as the Internet Watch Foundation . Does the Minister agree that there is a fundamental and very concerning lack of accountability when obscure technical groups, peopled largely by the employees of the big internet
companies, take decisions that have major public policy implications with enormous consequences for all of us and the safety of our children? What engagement have the British Government had with the internet companies that are represented on the Internet
Engineering Task Force about this matter?
Lord Ashton of Hyde The Parliamentary Under-Secretary of State for Digital, Culture, Media and Sport
My Lords, I thank the noble Baroness for discussing this
with me beforehand, which was very welcome. I agree that there may be serious consequences from DoH. The DoH protocol has been defined by the Internet Engineering Task Force . Where I do not agree with the noble Baroness is that this is not an obscure
organisation; it has been the dominant internet technical standards organisation for 30-plus years and has attendants from civil society, academia and the UK Government as well as the industry. The proceedings are available online and are not restricted.
It is important to know that DoH has not been rolled out yet and the picture in it is complex--there are pros to DoH as well as cons. We will continue to be part of these discussions; indeed, there was a meeting last week, convened by the NCSC , with
DCMS and industry stakeholders present.
Lord Clement-Jones Liberal Democrat Lords Spokesperson (Digital)
My Lords, the noble Baroness has raised a very important issue, and it sounds from the
Minister 's Answer as though the Government are somewhat behind the curve on this. When did Ministers actually get to hear about the new encrypted DoH protocol? Does it not risk blowing a very large hole in the Government's online safety strategy set out
in the White Paper ?
Lord Ashton of Hyde The Parliamentary Under-Secretary of State for Digital, Culture, Media and Sport
As I said to the noble Baroness, the Government attend the IETF . The
protocol was discussed from October 2017 to October 2018, so it was during that process. As far as the online harms White Paper is concerned, the technology will potentially cause changes in enforcement by online companies, but of course it does not
change the duty of care in any way. We will have to look at the alternatives to some of the most dramatic forms of enforcement, which are DNS blocking.
Lord Stevenson of Balmacara Opposition Whip (Lords)
My Lords, if there is obscurity, it is probably in the use of the technology itself and the terminology that we have to use--DoH and the other protocols that have been referred to are complicated. At heart, there are two issues at
stake, are there not? The first is that the intentions of DoH, as the Minister said, are quite helpful in terms of protecting identity, and we do not want to lose that. On the other hand, it makes it difficult, as has been said, to see how the Government
can continue with their current plan. We support the Digital Economy Act approach to age-appropriate design, and we hope that that will not be affected. We also think that the soon to be legislated for--we hope--duty of care on all companies to protect
users of their services will help. I note that the Minister says in his recent letter that there is a requirement on the Secretary of State to carry out a review of the impact and effectiveness of the regulatory framework included in the DEA within the
next 12 to 18 months. Can he confirm that the issue of DoH will be included?
Lord Ashton of Hyde The Parliamentary Under-Secretary of State for Digital, Culture, Media and Sport
Clearly, DoH is on
the agenda at DCMS and will be included everywhere it is relevant. On the consideration of enforcement--as I said before, it may require changes to potential enforcement mechanisms--we are aware that there are other enforcement mechanisms. It is not true
to say that you cannot block sites; it makes it more difficult, and you have to do it in a different way.
The Countess of Mar Deputy Chairman of Committees, Deputy Speaker (Lords)
My Lords, for the
uninitiated, can the noble Lord tell us what DoH means --very briefly, please?
Lord Ashton of Hyde The Parliamentary Under-Secretary of State for Digital, Culture, Media and Sport
It is not possible
to do so very briefly. It means that, when you send a request to a server and you have to work out which server you are going to by finding out the IP address, the message is encrypted so that the intervening servers are not able to look at what is in
the message. It encrypts the message that is sent to the servers. What that means is that, whereas previously every server along the route could see what was in the message, now only the browser will have the ability to look at it, and that will put more
power in the hands of the browsers.
Lord West of Spithead Labour
My Lords, I thought I understood this subject until the Minister explained it a minute ago. This is a very serious issue. I was
unclear from his answer: is this going to be addressed in the White Paper ? Will the new officer who is being appointed have the ability to look at this issue when the White Paper comes out?
Lord Ashton of Hyde The
Parliamentary Under-Secretary of State for Digital, Culture, Media and Sport
It is not something that the White Paper per se can look at, because it is not within the purview of the Government. The protocol is designed by the
IETF , which is not a government body; it is a standards body, so to that extent it is not possible. Obviously, however, when it comes to regulating and the powers that the regulator can use, the White Paper is consulting precisely on those matters,
which include DNS blocking, so it can be considered in the consultation.
