If I bought a domain like a9j47fn83jd8j49.tld, and only a friend and I ever visit it, who would know about it? It sounds like for most TLDs, there is some reporting that has to happen after you buy a domain, but does it always work like that?

Maybe having just ~4 billion IPv4 addresses makes this inevitable. In an IPv6 world, would it be harder to map out the whole internet? Not trying to rely on any secrecy necessarily, but I do notice that my personal sites always get scanned by bots very quickly, and it got me curious about whether it's inevitable that everyone knows every name out there. Certainly someone needs to know if a domain is taken or not, but that doesn't necessarily mean they always have to publish a list of all domains, right?

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    You cpuld create a subdomain - provided you run the nameservers for it you would have good visibility and control of it, and it would not automatically get into any lists.
    – davidgo
    Commented Dec 21, 2021 at 7:08
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    A domain is like a entry in the phone book, that you buy. Of course you can create your own phone book to use, but it's not "the" phone book then.
    – Thomas
    Commented Dec 21, 2021 at 13:40
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    @davidgo Sure, as long as clients only ever query a9j47fn83jd8j49.tld IN NS publicly, and only send queries like secret-subdomain.a9j47fn83jd8j49.tld IN AAAA to the authoritative nameservers for a9j47fn83jd8j49.tld over an encrypted channel, but ensuring this is impossible without bespoke tooling or doing everything by hand. Else, whatever recursive name server or middleman you're talking to will just learn the subdomains you're trying to resolve.
    – Jivan Pal
    Commented Dec 21, 2021 at 14:01
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    "are the players in the DNS system known to do much with the subdomains that they "overhear" day to day?" Yes they do. For multiple reasons, from research to combat malware, etc. "but it's imprecise, and I wonder how they attempt it." There are a lot of ways (and questions on this site or other SE ones so you can find details), but you can start by reading blog.appsecco.com/… Commented Dec 21, 2021 at 18:24
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    @JivanPal It is right in the introduction of RFC 7858 defining DoT: " This document focuses on securing stub-to-recursive traffic, as per the charter of the DPRIVE Working Group. It does not prevent future applications of the protocol to recursive-to-authoritative traffic." Yet, these applications do have further problems which is why it is still discuss. At least two: the load of TLS on servers and how to verify the certificates... Commented Dec 22, 2021 at 2:52

8 Answers 8


Is it possible to keep the existence of a domain secret?

Secret to whom? And incidentally, why does it need to be secret?

Secret to your OS, applications you use (including plugins in your browser, etc.), ISP, DNS resolver you use (any public one?), registrar and registry involved, certainly not. Which makes already a long list.

(Add to that, potentially, any government or governmental agency of any country in which any of the entities in the above list reside).

Maybe having just ~4 billion IPv4 addresses makes this inevitable.

You are slightly confusing 2 things here also. Registering a domain name does not force it to resolve. Yet the mere fact it was registered, and sometimes to whom, can be considered a valuable information (ex: new companies, or merges, or new movies or games, etc.)

Not trying to rely on any secrecy necessarily, but I do notice that my personal sites always get scanned by bots very quickly

So that is another question, which may have multiple answers. What do you mean exactly by "personal sites"? And why it is a problem that the "bots" (which ones?) do come see your site?

And is it related to when a domain is registered or when you switch ON a new server with a new site attached to it?

They are numerous ways, and the below is certainly not exhaustive:

  • as, albeit wrongly, the other 2 answer states, they exist zonefiles, for gTLDs; almost anyone can get access to them, but it is updated only daily, so that can't explain a visit right after registering a domain
  • your ISP can look at your traffic, and resell patterns. Typically at the DNS level if you use them as DNS recursive resolver, but same for any public resolver you may use, how do you know about its policy regarding data?
  • multiple applications (ex: Skype) scan links in message, purposedly to detect harmful content, but that also mean as soon as you exchange a message with a link, you will get an hit on it; even private things; various other vendors or OS can have the same things, including in smartphones
  • with the world going to HTTPS, browsers rely more and more on Certificate Transparency Logs; public CAs are mandated to publish the certificates they issue, and those certificates contain names; this is almost real time plus in fact the certificates are technically stored there even before the certificate is issued to end client
  • etc. (I only gave the examples above as something you may not think about but are clearly source of data)
  • Helpful points! Just to clarify "personal sites", I mean some sites I maintain that have 1-2 intended users, across 2-3 devices (e.g. me and a roommate). Bots could often be friendly, though I've been following that recent "log4shell" exploit, where the mere requesting of a URL could lead to compromise. (But I'm not running Java, so admittedly this is theoretical, and I know at least some of the log4shell attempts in my logs are from benign security-focused companies)
    – dcc310
    Commented Dec 21, 2021 at 2:14
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    "though I've been following that recent "log4shell" exploit, where the mere requesting of a URL could lead to compromise." Against that, trying to think to hide resources is not a solution. Because it is basically impossible to hide completely. If a resource is to be restricted to only some users, then restrict it (by IP, by authentication, etc.). Otherwise monitoring and security updates are the only practical way to go. Commented Dec 21, 2021 at 3:14
  • @PatrickMevzek "If a resource is to be restricted to only some users, then restrict it (by IP, by authentication, etc.)" This. You could even do something like MAC address if it's just you and a couple friends. Not as limiting as IP, no extra auth steps, still limited to your short list. This is not secure for "real" applications, it's an idea to compromise convenience with blocking most/all automated attempts at access
    – TCooper
    Commented Dec 21, 2021 at 19:02
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    @TCooper " You could even do something like MAC address" Doesn't work out of a local network (same WiFi for example). Plus otherwise, in "public", MAC addresses are not authenticated and hence can be spoofed. Commented Dec 22, 2021 at 2:55

No not possible. ICANN, the org maintaining DNS provides something that's called Centralized Zone Data Service (CZDS). Which provides lists of all registered domains.

Here is a bunch of info on that: https://czds.icann.org/help

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    That is only for gTLDs, not ccTLDs. Commented Dec 21, 2021 at 0:35

They do have a list of all domains.

Agencies responsible for many TLDs (top level domain, e.g. .com), publish a zone file, a list of all registered domains in that TLD, along with their DNS servers. It is downloadable as a flat file.

As such, people trying to find all domains simply do that. They don't bang on every IP address, and anyway, that wouldn't tell them about the domains on that IP.

However certain TLDs do not publish zone files. They probably publish new domain names in other ways, however. "Security through obscurity" doesn't work that well.

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    "Every agency responsible for every TLD (top level domain, e.g. .com), publishes a list of all registered domains in that TLD, along with their DNS servers. It is downloadable as a flat file." That is absolutely NOT TRUE. Zonefiles (or zone transfers) are available for root, and all gTLDs, per ICANN rules. Certainly not for all ccTLDs. Try to find the zonefile for .de or .fr... good luck! Commented Dec 21, 2021 at 0:35
  • @PatrickMevzek corrected, thanks. Yeah, I was never able to get those. Commented Dec 21, 2021 at 1:35
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    I still disagree with "However certain TLDs do not publish zone files. Choosing one of them may help with your attempt at "security through obscurity". for many reasons outlined in my answer. For example .fr does not publish a zonefile but publishes a list of daily new names. Commented Dec 21, 2021 at 3:13
  • @Patrick OK I'll fix that too. Commented Dec 21, 2021 at 4:57
  • Not publishing the zone file doesn't really help. As long as the TLD is DNSSEC-compatible, it's trivial to iterate the whole zone by following the NSEC chain. NSEC3 does not preclude this, just makes it more clostly, but the cost is well within practicality thanks to "other prominent applications" of brute forcing hashes. Commented Dec 22, 2021 at 18:18

Consider this:

How did you ensure a9j47fn83jd8j49.tld wasn't already taken before buying it?

If your goal is to not be found out then you need to have a local network, a web server, a router-level DNS entry for your domain, and you both need to use a VPN to get to this network and view the website.

  • This is the best thought experiment for this question.
    – justhalf
    Commented Dec 24, 2021 at 5:43

Alternative of what you are describing might be a Tor hidden service (<random>.onion) and requiring a Tor cookie(v2) or RSA key-pair(v3). That way even though it'd be published (and still rather annoying to retrieve the name), Tor itself would prevent the access to the service for you. Then again, you could just require cert auth via a clearnet webserver, however there's a difference in the DNS name owner's anonymity.

So for the use-case of only you and your friend accessing it, it'll work just fine and even if somebody knew the random name, it wouldn't matter because there's no legal document binding to it (or in other words, one can spawn N new domains in a while loop and nobody knows who it is). For the clearnet DNS record, there's at least the DNS registrar + its connected nodes that will be knowing the name and perhaps even doing a visit to it, you can't never know.


I'm not sure why you wish to keep the domain name secret, or why you want a domain name at all if just you and a friend or two will access it. If you're thinking it can provide security, keep in mind that a hacker can just use the IP address directly without bothering with a domain name.

If you just want to make it easier than having to enter the IP address, you could consider skipping the domain registration entirely and just entering a fake domain name in the "hosts" file of any PC that will be used to access it. That wouldn't help if you're wanting to access it via a phone, but depending on your situation, it might be the simplest solution. Under Windows, the file is at C:\Windows\System32\Drivers\etc\hosts.

  • Well, my question is a bit theoretical. I do want my particular sites to be discovered, at the end of the day! In terms of motivation, if people could pay for "unlisted" sites, I bet they would sometimes choose that, like they often opt to have secret Google Docs / Pastebin links, which are accessible from anywhere in the world without authentication. (Though I'm also not saying the Internet should have been built this way)
    – dcc310
    Commented Dec 22, 2021 at 22:30
  • Your point about the "hosts" file is a good one. Also, in terms of hackers accessing IP addresses directly, I assume it's feasible and commonplace for a single actor to hit all possible IPv4 addresses over time. But the space of possible domain names or IPv6 addresses is enormous (thus my mention pf it in the original question)
    – dcc310
    Commented Dec 22, 2021 at 22:38
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    Web servers can be (and should be, in my opinion) configured to show an error page for IP address requests without a host name. Commented Dec 23, 2021 at 11:55

No... but also Yes!

No, in the typical sense of purchasing and registering a domain name, because the point of registering something is to make it publicly discoverable. Other answers have this covered.

But Yes (for what it sounds like you want to achieve), because the same effect can be achieved by customizing the DNS settings of the devices accessing the site, or the router those devices are on.

Consider Pi Hole, the popular software for ad blocking, among other things. Setting up a Pi Hole as the DNS server on your device/network makes it fail to resolve domain names that are on your block list, thus blocking ads. You could configure a similar DNS server (or possibly even Pi Hole itself) to resolve any arbitrary domain as any arbitrary IP, whether that domain is registered or not.

Doing this from anywhere would require hosting that DNS server online. Insert obligatory boilerplate about network security, if you would consider forwarding a port from your home network


A secret domain is a oxy-moron. The whole idea of registering a domain is so that the domain can point end-user to your web servers IP address. If you only have a couple of users you can easily setup your own web server with apache or ngx and just send your friend your IP address, but this would not use a domain. You can auctually visit most website by just entering there IP address in your web browser. Although knowing which one serves your area may be tricky. You may find that out of the 20 - 30 IP addresses that serve YouTube only a certain few will auctually serve your web browser any files.

Also you seem to be confusing domains with IP address. Big sites like YouTube have multiple IP addresses that all serve the same domain. If you want to forbid Google from crawling your website you can always use the noIndex directive in the head tag of you html.

  • "just send your friend your IP address, but this would not use a domain." and it won't work at all for things like HTTPS because of the certificate check (that is based on a name, and not an IP address). So no, just having an IP address instead of a name is not good to establish a connection nowadays. Plus, even outside of certificates and HTTPS, even in HTTP you can have multihoming (multiple servers/websites on the same IP address) so you need to have a name to resolve things at HTTP layer. Commented Dec 22, 2021 at 18:06
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    "This is in fact how much of the illegal content on the dark web is disseminated." Not at all. What is often described as the dark web is basically Tor, which uses .onion names. Commented Dec 22, 2021 at 18:07
  • "You can auctually visit most website by just entering there IP address in your web browser." Care to give examples for HTTPS? Commented Dec 22, 2021 at 18:07
  • Since you're probably looking for examples where you don't have to create a security exception (I think self-signed certs are perfectly reasonable for a just-for-friends service. Anyway): (Not sure whether you have to own a CA to pull this off. Also, if you get a CA signed cert, does your IP still count as secret?)
    – Caesar
    Commented Dec 24, 2021 at 7:05

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