{"id":10200,"date":"2019-04-23T12:59:17","date_gmt":"2019-04-23T16:59:17","guid":{"rendered":"https:\/\/www.thesslstore.com\/blog\/?p=10200"},"modified":"2023-04-10T09:38:43","modified_gmt":"2023-04-10T13:38:43","slug":"what-is-a-dns-leak","status":"publish","type":"post","link":"https:\/\/www.thesslstore.com\/blog\/what-is-a-dns-leak\/","title":{"rendered":"What Is a DNS Leak?"},"content":{"rendered":"\n

What causes a DNS Leak and what can be done to fix one?<\/h2>\n\n\n\n

Do you remember the first time you grew a little bit concerned about your digital privacy? Maybe it was the first time you figured out the ads you\u2019ve been seeing are specifically targeted to you. Maybe it was Google\u2019s eagerness to be helpful that betrayed just how much information it has about you (it knows where you are right now). Or maybe you\u2019ve never really considered these things and today\u2019s discussion about DNS leaking will really open your eyes. <\/p>\n\n\n

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\"What<\/figure>\n<\/div>\n\n\n

If that\u2019s the case, I envy you. In fact, maybe even consider just taking a rain-check on the rest of this article and then just continue living your life \u2013 because ignorance truly is bliss. <\/p>\n\n\n\n

But for the rest of us, privacy is an unfortunate consideration in many of the decisions we make online. <\/p>\n\n\n\n

And when it comes to our digital privacy, DNS leaks are a\nparticularly pernicious threat to said privacy. But despite their ability to\ncompromise your anonymity, DNS leaks are also one of the least understood\nthreats faced by the modern internet user. That\u2019s owing to a lot of different\nfactors, chief among them that aforementioned blissful ignorance.<\/p>\n\n\n\n

If we\u2019re being honest, the average internet user doesn\u2019t understand how the connections being made by their own computer actually work, nor do they understand the Internet Protocol, IP addresses, the Domain Name System or even Virtual Private Networks. In turn, that lack of information makes everything else feel abstract and basically blunts any concern we would otherwise have about the threat.<\/p>\n\n\n\n

So, today we\u2019re going to talk about DNS Leaks, what they\nare, why they\u2019re dangerous and how to fix them.<\/p>\n\n\n\n

Let\u2019s hash it out.<\/span><\/p>\n\n\n\n

Internet Connections and VPNs<\/h2>\n\n\n\n

If you\u2019ll recall a few weeks ago we went in-depth on the TCP\/IP model for network connections<\/a>. If you want a complete explanation of all that, I recommend checking it out. But for now, here\u2019s the abridged version:<\/p>\n\n\n\n

Anytime you make a connection on the internet, data is being routed across multiple layers, in multiple ways, to facilitate the connection itself. In fact, calling it a singular connection can even be a little misleading as there are actually multiple connections being made throughout the process. Of course, this all happens in the background, so for most of us our only exposure to a lot of it is the error messages that are triggered when something goes wrong (TLS handshake error<\/a>, I\u2019m looking at you). <\/p>\n\n\n\n

So, while on the user side visiting a website might seem as straightforward as typing \u201camazon.com\u201d into your address bar and within seconds you\u2019re connected to Amazon. But that belies just how complicated making that connection actually was. <\/p>\n\n\n\n

Let’s illustrate with an example. Here\u2019s a quick breakdown of what a mail connection would look like:<\/p>\n\n\n

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\"How<\/figure>\n<\/div>\n\n\n

Again, we\u2019re not going to go too far into the weeds on thre of the four layers you see here, instead we\u2019re going to focus in on the Network Layer where the Internet Protocol functions. <\/p>\n\n\n\n

The top two layers, Application and Transport, largely deal with the defining the connection itself. What port will it use. What connection type (TCP or UDP). Data is ported, segmented and put into transmittable packets. <\/p>\n\n\n\n

On the Network Layer you\u2019re handling the connection between different networks via the Internet Protocol and the networks\u2019 respective IP addresses.<\/p>\n\n\n\n

You\u2019re likely familiar with IP addresses, but you might not know why they\u2019re significant. While Google has plans to kill it<\/a>, colloquial use of the internet has always relied on the URL or Uniform Resource Locator. Asking people to remember strings of numbers has historically not been a good idea. Our cell phones have largely eliminated the problem, but before everyone had a mobile device in their pocket, remembering phone numbers was a huge pain in the rear. (Also, using Maps.) People often had to carry around black books full of phone numbers or else record them on the walls of bathroom stalls for their use in perpetuity. <\/p>\n\n\n

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\"\"<\/figure>\n<\/div>\n\n\n

So, asking you to remember an IPv4, or even worse an IPv6 address is going to yield a lot less success than just rolling with a URL like \u201ccompany.com.\u201d People remember \u201ccompany.com.\u201d Thus, we use URLs.<\/p>\n\n\n\n

But that creates its own issue, now you need to keep a dedicated resource that serves as a de facto phone book, pairing URLs with their respective IP addresses. But given the fact the internet is constantly growing, that websites can change IP addresses, and considering the amount of space that would be required to keep an ongoing record of all that, how do you reconcile letting users use URLs when networks and websites use IP addresses? <\/p>\n\n\n\n

The Domain Name Service or DNS. <\/p>\n\n\n\n

DNS is that resource. In the example above, after the information has been segmented and ported, it needs to be delivered to the correct network. In order to do this, the Internet Protocol will likely be used, which will require the correct IP address to be affixed to the data in the form of a header that will be used to route it to the correct destination.<\/p>\n\n\n\n

But in order to get the correct IP address, you\u2019re going to need to perform a DNS look-up.<\/p>\n\n\n

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\"How<\/figure>\n<\/div>\n\n\n

This occurs on the network layer. Before the data can be\nrouted to its intended recipient, the sender\u2019s computer system or network is\ngoing to need to reach out to a DNS server or resolver to pair the given URL\nwith its IP address. This is a highly technical step that many people never\ngive a second thought to. But if you\u2019re worried about your privacy this is also\none of those critical steps in a connection that can effectively muck up everything.<\/p>\n\n\n\n

Here\u2019s why\u2026<\/p>\n\n\n\n

What\u2019s the Big Deal About a DNS Leak?<\/h2>\n\n\n\n

Ideally, in a perfect world, you wouldn\u2019t need to worry about your DNS lookups being a problem. Guess what, that\u2019s not the world we live in. This issue really plays out on two different levels depending on your geography. But before we get to that, let\u2019s contextualize just a little bit more by bringing VPNs into this conversation.<\/p>\n\n\n\n

People use VPNs for two primary reasons: <\/p>\n\n\n\n