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steven36 posted a topic in Security & Privacy NewsIt makes sense to shield even the names of sites you visit from spying eyes. But it’s being done in a kludgy, centralized fashion that’s far from ideal. As the internet has shifted to securing data and encrypting traffic by default, one surprising privacy hole has remained, which leaves a trail of sites you visit open to sniffing by network ne’er-do-wells. A proposal to remedy this is being rolled out slowly—by Mozilla in its Firefox browser and by Google in Chrome. This new technology approach, called DNS-over-HTTPS (DoH), can shield your browsing habits from ISPs such as AT&T, Comcast, and Verizon, who have at times showed a propensity to track users by using supercookies and other techniques. (Sean Captain offers advice on how to use DoH in “Here’s how to stop Comcast, Verizon, and other ISPs from spying on you.”) But security can be a two-edged sword. This technology for shielding your actions from ISPs, public hotspots, and other institutions has the potential to introduce a new privacy risk: the centralization of browsing habits. It also highlights existing privacy leaks that DoH doesn’t solve and could exacerbate. What’s in a name? Everything Unless you use a virtual private network (VPN) connection, someone with access to a public network you use can determine every web site you visit, every email server you contact, and every other kind of online server your mobile device or laptop connects with, even when each connection is encrypted. This is also true on any shared network in which network traffic isn’t shielded from other users on the same network, or which administrators can monitor. That’s because of the last truly exposed plumbing fixtures of the old internet: DNS, or domain name service. DNS is an ancient system developed when the number of computers on the internet outpaced people’s ability to manually update lists of them. Yes, it’s that old. Instead, DNS provides a way to map a human-readable and typeable name, such as fastcompany.com, to the appropriate machine-oriented address, like 220.127.116.11 or 2607:f8b0:4004:814:200e. (The former number uses the long-running IP version 4 notation; the latter, IPv6, allows for vastly more unique numbers and has rolled out slowly as an eventual replacement for IPv4.) Not only do you not want to type those numbers in or memorize them; DNS has grown vastly in complexity since its early days, allowing a single name to map to many different machine identities to allow “round-robin” access that helps balance traffic loads. It’s also used by content-distribution networks (CDNs), such as Akamai and Amazon CloudFront, to offer a server address that’s geographically closest to the device requesting it, reducing the number of internet hops and thereby improving performance. And DNS is also a way to stash a lot of other additional information related to a domain and its owners. So-called text (TXT) records allow any arbitrary information to be added to a DNS entry. Google allows a TXT record to verify a domain ownership, just like a message is sent to an email address to validate that someone has access to that mailbox. When you make a network connection via Wi-Fi, Ethernet, or cellular, one of the things your device receives is a list of DNS servers. Your device sends the query to the DNS server, which consults a master list of all TLDs (top-level domains), like .com, .aero, and .uk. Using a hierarchy from right to left, separated by periods, the DNS server eventually finds an “authoritative” DNS server that provides an answer, and then that answer is handed back to your device. Not exactly simple, but at least somewhat straightforward. For instance, a browser trying to reach fastcompany.com starts by consulting the .com hierarchy for where fastcompany.com has its entries stored—the servers that feed out DNS information are called “nameservers”—and then consults the fastcompany.com nameserver directly to receive the records required to create a direct connection by machine address. Fast Company uses a CDN, like most sites that see a lot of traffic, and the machine address you receive may be different from someone 2,000 miles away, or possibly even 100 miles away. The trouble is that every time a DNS lookup occurs, the domain names are sent in the clear, even if the rest of the communication is encrypted, as web and email connections are likely to be, thanks to the massive uptake of encryption in the post-Snowden era. A PC might send thousands of DNS requests a day, due to all the tracking components and third-party elements used on modern websites. Because of CDN retrievals, someone monitoring domain lookups and the IP address responses may be able to derive a cluster of information about your habits and whereabouts, sometimes with incredible granularity. DNS is fusty and obscure. It’s such a mess that in 2008, security researcher Dan Kaminsky uncovered a fundamental flaw that affected nearly every operating system and server in the world. He worked diligently to keep it secret until Apple, Microsoft, Google, and other firms could paper over it. (It’s never been fully fixed.) In 2015, a bug in a popular DNS server—software that handles responding to queries—allowed trivially easy denial-of-service attacks. DNS also lacks verification, allowing “DNS poisoning,” in which a wrong answer can be provided to a device asking for a domain name lookup without that device being able to know the answer was subverted. This is most likely to happen at a coffee shop or other public network, but it can happen on a country-wide level too. DNS-over-HTTPS would fix privacy and some of the integrity issues. Instead of a DNS query being passed in the clear and using the local network’s DNS server, Firefox and Chrome effectively create a VPN only for DNS. The query is sent through an encrypted tunnel to a central service that provides the answer. This prevents local poisoning and interception locally and at all points in between. The entity running the central server can perform queries to other DNS servers to retrieve answers without leaking anything about the requesting parties too. But it’s the “central” part that’s a problem. Who watches the DNS watchmen? The trouble with DoH isn’t its concept. Rather, it’s in how different browsers propose to enable it by default in upcoming releases. Mozilla’s Firefox is starting with U.S. users only, after testing for over a year and picking Cloudflare as its anointed partner. Google will soon begin testing DoH in Chrome but will initially only enable it for people who have already chosen a set of ISPs that have a DoH option available. Most consumers have DNS service provided by their ISP, either through preconfigured settings in a router provided by the ISP or by entering the IP addresses for DNS servers provided by the ISP. (In a chicken-and-egg problem, a DNS server is required to look up a name, so you have to start by entering the IP addresses for servers to prime the pump.) Millions of people and organizations have already shifted from ISP-provided DNS to one of several public DNS providers, such as Google, OpenDNS, and Cloudflare. These services arose when most ISPs ran DNS servers without much care, leading to lengthy delays as sites were looked up. Well-optimized public DNS sped that up. The end result is a de facto centralization of DNS, with most users entrusting their internet activity to a few huge companies, such as Comcast, Verizon, and Google. However, DoH could centralize that further. While Google’s Chrome tests will simply upgrade users who have already picked one of a few public DNS providers who are already offering DoH, Mozilla will shift people’s Firefox browsing from relying on their ISP or public DNS to Cloudflare’s DoH offering. (Parents who use a filtering service that relies partly on DNS for blocking and corporate users with internal-only DNS lookups will be opted out of DoH, though how effectively remains to be seen.) Even though DNS by itself is insecure, it’s also a sort of jumble that makes it hard to track back and associate a set of DNS requests from a single device. By creating secure https connections, DoH allows all requests to be strongly associated. Centralization provides strong incentives for organizations that have access to data to engage in off-white, gray, and black hat behavior. “Beige” companies might be tempted to aggregate “anonymous” information that can be reassociated with individuals or used to extract insights that DoH users haven’t directly consented to provide. Ethically ambiguous parties might extract or attempt to intercept information about connections. And outright black-hat crackers could focus all their energy on penetrating the security of firms offering centralized services. DNS is a hoary protocol, and DoH is stapled on top of it. Many other objections have been raised to a variety of competition- and privacy-reducing aspects that critics call “Centralized DoH.” A draft paper submitted to the IETF (Internet Engineering Task Force) notes that the rapid deployment of this mode skips over the fact that ISPs are interested in or planning to deploy DoH service and that shifting to central DoH bypasses protections and agreements in place between ISPs and customers. Three of the paper’s four authors work for big ISPs: BT, Comcast, and Sky. And many of the concerns raised are identical to public DNS, such as creating fewer, bigger single points of failure, reducing the number of people who understand and work on maintaining and improving DNS software, and concentrating power in fewer hands with less responsibility. However—and it’s a big however—people who use public DNS have almost always made a conscious decision to do so. With Mozilla’s Firefox move, users are being pushed into DoH. Google’s initial plan for Chrome isn’t as aggressive, but that could change. The folks behind the open-source PowerDNS lay out a host of reasons why centralized DoH adds additional privacy leaks, because while DNS already spews data all over the place, pushing DoH to one location adds additional parties into the mix and more direct session tracking. Expedient, but not ideal Securing DNS is way overdue. As a cranky old piece of the internet’s lifeblood, it’s baked in so deeply and it’s so decentralized in its nature that it—like mail server communications—is hard to upgrade without scrubbing the slate clean. But hasty action is often worse than considered plans. DoH would work best at an operating system level or as a user-installed system-level component, where it can be used as a proxy for all DNS queries—not just in a browser, but for all services. While ISPs have their own privacy issues regarding their users, the direct financial relationship for service provides the potential for more accountability than if DoH is provided by a third party you aren’t paying. DoH has been cited as a way for people at risk of action by their governments or populations in repressive countries to avoid scrutiny. But single points of service, like central DoH addresses, are far easier to block than VPNs that constantly shift IP ranges to evade censors and government agents. If you don’t use a VPN on insecure networks—whether they’re managed by a coffee shop or an entire country—DoH is a potential improvement. But a VPN is a choice and one you can evaluate and implement. Centralized DoH, by contrast, appears to be on a path to becoming a de facto piece of plumbing rather than something individuals choose to buy into. DNS’s future is encryption, but centralizing a service that has thrived in its creaky, weird old way for decades is only an expedient solution, not a great one. Source
steven36 posted a topic in Security & Privacy NewsDoH support is already present in all major browsers. Users just have to enable it and configure it. All six major browser vendors have plans to support DNS-over-HTTPS (or DoH), a protocol that encrypts DNS traffic and helps improve a user's privacy on the web. The DoH protocol has been one of the year's hot topics. It's a protocol that, when deployed inside a browser, it allows the browser to hide DNS requests and responses inside regular-looking HTTPS traffic. Doing this makes a user's DNS traffic invisible to third-party network observers, such as ISPs. But while users love DoH and have deemed it a privacy boon, ISPs, networking operators, and cyber-security vendors hate it. A UK ISP called Mozilla an "internet villain" for its plans to roll out DoH, and a Comcast-backed lobby group has been caught preparing a misleading document about DoH that they were planning to present to US lawmakers in the hopes of preventing DoH's broader rollout. However, this may be a little too late. ZDNet has spent the week reaching out to major web browser providers to gauge their future plans regarding DoH, and all vendors plan to ship it, in one form or another. How to enable DoH in each browser Below are what we currently know about each browser vendor's plans regarding DoH, and how users could enable DoH in each respective browser. Brave "We absolutely want to implement it," Tom Lowenthal, Product Manager at Brave for Privacy & Security told ZDNet yesterday. However, the Brave team doesn't yet have an exact timeline for DoH's rollout. This is because Brave developers have been busy with other privacy-focused improvements. For example, yesterday, the company released an update with improved detection of user fingerprinting scripts. Further, the v1.0 stable release is on the horizon, so the Brave team needs to focus on that release first. Nevertheless, DoH will come to Brave. "Implementing DoH is far more than just the technical work, though. We need to decide on sensible and protective defaults for the vast majority of people who don't think about their DNS configuration while making sure that we don't break things for the people and organizations who have carefully tuned their setup," Lowenthal said. Because Brave is built on top of the Chromium open-source browser codebase, DoH support is available. However, the Brave team has not configured the feature to its own liking. It is there in the codebase, but in the way the Google Chrome team designed it to work (see Chrome section below). You can enable DoH in Brave by visiting the following URL: brave://flags/#dns-over-https Chrome Google Chrome is the second browser after Firefox to have added DoH support. You can enable DoH in Chrome by going to: chrome://flags/#dns-over-https DoH isn't turned on by default for everyone. Google is currently running a limited experiment with a small number of users to see how DoH fares in a real-world test. Details here. Unlike Firefox, which forces all DoH traffic to Cloudflare by default, Chrome's DoH support is different. After DoH is enabled in Chrome, the browser will send DNS queries to the same DNS servers as before. If the target DNS server has a DoH-capable interface, then Chrome will encrypt DNS traffic and send it to the same DNS server's DoH interface. This prevents Chrome from hijacking an operating system's DNS settings, a sensible approach in enterprise environments. Currently, Chrome's DoH support works like this: - a user types a website URL in the browser - Chrome looks at the operating system's DNS server - Chrome checks to see if this DNS server is on a whitelist of approved DoH-capable DNS servers - if yes, Chrome sends a DoH (encrytped) DNS query to that DNS server's DoH interface - if not, Chrome sends a regular DNS query to the same server Because of the way Google implemented DoH support in Chrome, users risk of never being able to use DoH. This is because a user's operating system gets its DNS settings from a central network authority, which is usually the ISP. If the ISP doesn't want to use a DoH-friendly DNS setting, then you're never going to have DoH in Chrome. The good news is that there are two ways of bypassing this and forcing Chrome to use DoH all the time, regardless of your ISP's DNS settings. First, there's this tutorial to forcibly-enable DoH in Chrome. Second, a user can configure a custom DoH-friendly DNS server for their operating system. They can choose one from this list, guaranteed to work in Chrome. Edge Next year, Microsoft plans to roll out a new version of its Edge browser, rebuilt on the Chromium codebase. A Microsoft spokesperson told ZDNet the company is supportive of DoH, but they couldn't share their exact plans. However, the Chromium-based version of Edge already supports DoH. Users can enable it by visiting: edge://flags/#dns-over-https This will turn on DoH, but it won't work unless your computer is using a DoH-capable DNS server -- which in 99% of cases, they are not. To forcibly enable DoH in Edge and work at all times, you can follow the steps laid out in the tweet below. You can replace the address of the Cloudflare DoH resolver with any other DoH server you want. You can choose one from here. Once configured properly, Edge is capable of running over DoH -- see screenshot below. Firefox Mozilla was the organization that pioneered DoH's creation together with Cloudflare. Support for DoH is available in stable versions of Firefox already. You can enable it via the browser's Settings section, in the Networking section. See instructions here. The reason why everyone has and is criticizing Firefox's DoH implementation is that they're using Cloudflare as the default DoH server for everyone, effectively overwriting local DNS settings for everyone. However, anyone can change this default setting to any other DoH server they want. Of all browsers, Firefox's DoH support is the strongest and easiest to configure, primarily because they've been working on it for longer than anyone else. The organization is currently enabling DoH by default for all users in the US. DoH won't be enabled by default for UK users, following the UK government's pushback against the feature. In the past, Mozilla was non-commital on its plans to enable DoH by default in other geographical areas outside the US. However, since DoH support is already present in the browser's stable release, all a user has to do is enable it, and it will work without any glitches. Opera Opera has already rolled out DoH support. The feature is turned off for all users but can be enabled at any time in the stable release, and it will work without users going through any additional steps. This is because Opera devs are using a default DoH resolver, similar to Firefox, and are not leaving it to ISPs, like Chrome. All Opera DoH traffic is currently funneled to Cloudflare's 18.104.22.168 DoH resolver. We couldn't find a way for users to change the DoH resolver to a custom server, but at least DoH is working in Opera. It won't work, however, if you're using Opera's built-in VPN system. The VPN feature must be disabled for DoH to work. To enable DoH in Opera, visit: opera://flags/opera-doh Safari No reply. However, Safari devs are usually late to any feature-rollout party, and Apple has been recently investing in user privacy-focused features, so the chances are pretty high that DoH will come to Safari. Vivaldi A Vilvadi spokesperson said that its DoH support is closely tied to Chrome's implementation. Users can enable it by visiting: vivaldi://flags/#dns-over-https However, because DoH in Vivaldi works just like in Chrome, it will not encrypt DNS queries unless a user is using an OS-wide DNS server that also has a DoH interface, and is listed on this page. Most likely, you'll need to add one of those DoH friendly DNS servers to your operating system's DNS settings if you want to make DoH work in Vivaldi, and use it all the time. We got it working by using 22.214.171.124 as our operating system's DNS settings. A Vivaldi spokesperson said Vivaldi's DoH support might change in the future, based on how Google changes Chromium's DoH support. Source
SwissMiss posted a topic in Security & Privacy NewsA Controversial Plan to Encrypt More of the Internet The road to routing all Domain Name System lookups through HTTPS is pocked with disagreements over just how much it will help. ILLUSTRATION: ELENA LACEY; GETTY IMAGES The security community generally agrees on the importance of encrypting private data: Add a passcode to your smartphone. Use a secure messaging app like Signal. Adopt HTTPS web encryption. But a new movement to encrypt a fundamental internet mechanism, promoted by browser heavyweights like Google Chrome and Mozilla's Firefox, has sparked a heated controversy. The changes center around the Domain Name System, a decentralized directory that acts essentially as the internet's address book. When you send data to or request it from a server, a DNS lookup ensures that it goes to and comes from the right place. Google and Mozilla plan to encrypt those interactions sometime this year. Which sounds straightforward enough—but not everyone is convinced that the shift solves more problems than it potentially creates. Reach For My Resolver The concept of DNS was developed in the mid-1980s, and hasn't evolved much since the early 1990s. Like many foundational internet protocols, DNS has been remarkably flexible and serviceable over the years. But having roots that predate the rise of the modern internet has led to inevitable problems, one of which is that those address lookups aren't encrypted. That’s a big deal. Any time your browser attempts a DNS lookup, that request can pass across multiple servers. Your internet service provider, lurking government snoops, and just anyone on the same Wi-Fi network can see what websites you visit, even if they can't see what you do once you actually load the sites. It gets even worse. Since DNS requests are unencrypted, bad actors can manipulate them to strategically send you to the wrong website. It’s like listing your address under someone else's name, and getting all their packages delivered to your house. This type of attack, known as DNS hijacking, has been on the rise; in January, the Department of Homeland Security even issued an emergency directive about the threat. "Yeah it’s going to be work, but that’s fine, just do the work." Matthew Prince, Cloudflare Which explains the push for encrypted DNS: It would make those types of surveillance and misdirection much harder. The Internet Engineering Task Force standards body has already codified a few different methods for implementing it, namely “DNS over HTTPS” (DoH) and “DNS over TLS” (DoT). Both protocols apply ubiquitous web encryption to DNS requests. The two standards are very similar, except DoT separates encrypted DNS traffic into its own recognizable channel (an attribute network defenders largely prefer), while DoH intermingles encrypted DNS traffic with general HTTPS encrypted web traffic so they're indistinguishable (an additional privacy benefit to some). Each approach has its pros and cons, but both Mozilla and Google have elected to go with DoH in their browsers. No matter which version you choose, though, adding a layer of encryption to DNS requires some systemic rejiggering. It's like writing down your order at a restaurant, locking it in a small safe, and then handing the safe to the waiter to take back to the kitchen. You won't give away any personal information about your culinary preferences, but you also won't get the right meal. To get around this complication, secure DNS protocols rely on intermediaries called "resolvers," which can still see the requests unencrypted as they come through. Mozilla has piloted its encrypted DNS with the internet infrastructure company Cloudflare acting as the main resolver. Cloudflare has already been offering encrypted DNS with a service called 126.96.36.199 for more than a year. Mozilla chose the company because it pledged to delete all DNS logs after 24 hours, never share data with third parties, and submit to audits to confirm that data is really being deleted. But users can set Firefox to default to any resolver that supports DoH. Similarly, Chrome is starting out by offering DoH with six resolvers, including Cloudflare and Google itself. That centralization of DNS requests worries detractors. Unlike end-to-end encrypted messaging, in which only you and the person you’re talking to can read the messages on each of your devices, encrypted DNS doesn’t quite succeed at boxing everyone out. It cuts telecoms and governments out of the equation in one way, but introduces new tech giants and third parties in another. "I would love it if there were 100 other encrypted DNS providers that customers could choose from," says Cloudflare CEO Matthew Prince. "We think that would be great. I get that there being a limited set of choices doesn’t feel good. But there's nothing proprietary about this. You can download open source software and run this today." The pro-privacy Electronic Frontier Foundation has acknowledged the concerns about consolidating DNS with so few resolvers, but recently suggested that the potential privacy benefits are worth the downside so long as more entities get into the space. Specifically, EFF called on internet service providers to start acting as encrypted DNS resolvers themselves. Ideally, this would involve getting ISPs to sign on to strict privacy protections like those Cloudflare has promised to adhere to as part of the process of adding support for DoH. That may not happen anytime soon, though. And even if it did, you can see how it would be difficult in practice to get entities already making money off of mining DNS data to really change their ways. A consortium of telecommunications trade associations wrote a letter to Congress in September opposing encrypted DNS and calling Google anti-competitive for starting to support it in Chrome. This argument seems specious at best, given that Chrome will be able to use a number of resolvers, not just Google’s. The overall effort, though, reflects how invested ISPs are in protecting their access to DNS data, seemingly so they can mine it to fuel targeted advertising. ISPs do also use insight into DNS requests to offer services like content filtering for children. House of Representatives investigators are currently assessing the letter’s claims. Safety First The ranks of DoH opponents aren't filled only with self-interested corporations. Cybersecurity professionals argue that encrypting DNS requests will make it harder to spot intrusions and malware on their networks, without truly giving web users a more private experience. Meanwhile, encrypted DNS advocates say that these concerns are overblown, especially for large companies that can just set up their own encrypted DNS resolver to access local traffic as before—although those measures aren’t necessarily feasible for the majority of organizations. “There are real operational and security implications of both DoH and DoT,” says Roland Dobbins, a principal engineer at Netscout Arbor. “Everyone needs to consider that things like identifying compromised devices and defending DNS infrastructure from DDoS attacks could become much more complex and costly.” DDoS attacks on DNS servers can have very real consequences. For example, a massive 2016 assault on the DNS provider Dyn caused widespread connectivity outages on the East Coast of the United States and around the country. "We're just trading who can potentially track us." Jake Williams, Rendition Infosec Researchers have already spotted malware built to evade detection by connecting to command and control servers using encrypted DNS requests. And another major concern is that if hackers were to compromise a trusted DNS resolver, they would be able to pull off devastating DNS hijacking attacks that wouldn't be detectable to the outside world. A similar issue already exists when hackers compromise the “certificate authorities” that underpin general HTTPS web encryption. Firefox and Chrome are still in the experimental phases of testing encrypted DNS, so most of your connections likely won't take advantage of it for now anyway, and there are still ways to opt out of using it at all. But as with the push to get websites to adopt HTTPS encryption, encrypted DNS will likely move forward now if Chrome and Firefox find that the change doesn’t have too much of an impact on speed or reliability for users. “Yeah it’s going to be work, but that’s fine, just do the work,” says Cloudflare’s Prince. “I’m astonished how political this has been. It makes me uncomfortable that every coffee shop I’m going to knows every site that I’m visiting. It seems like it’s a no brainer to be adding encryption. Let’s just do it!” For the average person, encrypted DNS will offer valuable privacy protections against ISPs and other entities that are hungry for user data. Even so, analysts caution that potentially risky web browsing should still take place with sturdier protections, like a VPN or the anonymity service Tor. Critics of DNS over HTTPS do recognize the irony of pushing for less encryption out of a desire to protect people when the security and cryptography communities overall take a hard line against law enforcement on the value of encrypted communication platforms free of backdoors. But the difference, they say, is that end-to-end encryption or encryption at rest cuts everyone out except the data's owners, while DNS encryption only shifts trust. “From an enterprise standpoint, DNS monitoring is critical to ensuring security. Losing the visibility into DNS is tremendous operational loss and will help attackers more than it ensures privacy,” says Jake Williams, a former NSA hacker and founder of the security firm Rendition Infosec. “As long as you trust resolvers like Cloudflare, then there's no issue. And I personally trust Cloudflare, but others may not. We're just trading who can potentially track us.” Vulnerable web users who've never given any of this a second thought—and don't even know what DNS is—would probably say, though, that they'll take whatever they can get. Source: A Controversial Plan to Encrypt More of the Internet
steven36 posted a topic in Security & Privacy NewsIn June, Mozilla had announced that they were performing a limited Shield study for their Nightly users to monitor the performance of DNS-over-HTTPS (DoH) in Firefox. This study uses Cloudflare's DNS service to encrypt both the requests and responses to any DNS queries in order to increase a user's privacy. Mozilla has been happy so far with the performance of DoH and have stated that even the slowest users have seen a huge performance improvement. Due to this, Mozilla is now expanding this Shield study to a small portion of the Release channel to get a wider audience testing their DNS-over-HTTPS feature. "Our initial tests of DoH studied the time it takes to get a response from Cloudflare’s DoH resolver," stated Mozilla's announcement. "The results were very positive – the slowest users show a huge performance improvement. A recent test in our Beta channel confirmed that DoH is fast and isn’t causing problems for our users. However, those tests only measure the DNS operation itself, which isn’t the whole story." As this expanded study will only roll out to a limited amount of users, not everyone who is currently using Firefox will have it enabled. For those who are picked to be part of the study, you will be shown an notification describing the study and asking if you wish to participate. For those who were not selected for the study, but still wish to test Firefox's DoH implementation, you can enable it manually using the instructions below. How to enable DNS-over-HTTPS (DoH) in Firefox Currently DoH is still being tested by Firefox, but if you want to start using it immediately you can enable it in the about:config settings. To enable DoH, please follow these steps: Type about:config in the Firefox address bar and then press enter. When Firefox asks, click on the button stating that you accept the risks. In the search field enter network.trr to display all of the settings for Firefox's Trusted Recursive Resolver, which is the DNS-over-HTTPS Endpoint used by Firefox. Double-click on network.trr.mode, enter 2 in the field, and press OK as shown below. This turns on DoH in Firefox. Next you need to make sure the network.trr.uri is set to https://mozilla.cloudflare-dns.com/dns-query as this is Cloudflare's DoH DNS resolver that Firefox has partnered with for the test. If it is not set to this URL, please double-click on the setting and enter the URL. You can now close the about:config page. To test whether you are now using DoH to resolve DNS queries, you can go to Cloudflare's Browsing Experience Security Check page and click the "Check my browser" button. The web page will now perform a variety of tests to see if you are using Secure DNS, DNSSEC, TLS 1.3, or Encrypted SNI. If DoH is enabled correctly it should report that Secure DNS and TLS 1.3 are enabled . Source