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  • I am looking for a domain name registrant. Where can I look it up?

    The Whois is an easy-to-use tool for checking the availability of a .nl domain name. If the domain name is already taken, you can see who has registered it.

    On the page looking up a domain name you will find more information about what a domain name is, how the Whois works and how the privacy of personal data is protected. Alternatively, you can go straight to look for a domain name via the Whois.

  • I would like to transfer my domain name to another registrar. What is the procedure?

    To get your domain name transferred, you need the token (unique ID number) for your domain name. Your existing registrar has the token and is obliged to give it to you within five days, if you ask for it. The procedure for changing your registrar is described on the page transferring your domain name.

  • The details registered about me/my company are incorrect or out of date. How can I get them updated?

    To update the contact details associated with your domain name, you need to contact your registrar. Read more about updating contact details.

  • Why is my domain name in quarantine?

    When a domain name is cancelled, we aren't told the reason, so we can't tell you. You'll need to ask your registrar. The advantage of quarantine is that, if a name's cancelled by mistake, you can always get it back.

    One common reason is that the contract between you and your registrar says you've got to renew the registration every year. If you haven't set up automatic renewal and you don't renew manually, the registration will expire.

  • Ik heb een klacht over mijn provider/registrar. Kan ik daarvoor bij SIDN terecht?

    Wanneer je een klacht hebt over of een geschil met je registrar dan zijn er verschillende mogelijkheden om tot een oplossing te komen. Hierover lees je meer op pagina klacht over registrar. SIDN heeft geen formele klachtenprocedure voor het behandelen van een klacht over jouw registrar.

  • What conditions do I have to meet as a registrar?

    Would you like to be able to register domain names for customers or for your own organisation by dealing directly with SIDN? If so, you can become a .nl registrar. Read more about the conditions and how to apply for registrar status on the page becoming a registrar.

More frequently asked questions

Outdated IPv4-based internet unsuitable for peer-to-peer applications

NAT spoils gaming experience

  • Tuesday 12 February 2019

NAT (Network Address Translation) has proved very helpful, enabling the use of IPv4 to be greatly extended. However, we've also shot ourselves in the foot by deploying NAT so widely. Without a unique IP address, your computer is unreachable for the outside world. For peer-to-peer applications, the new workarounds necessitated by NAT are problematic: STUN, TURN, ICE and others slow down traffic and sometimes prevent connections being realised at all.

Although some people still see IPv6 as a solution for a problem that has never actually arisen — exhaustion of the IPv4 address supply — we take a very different view. All the IPv4 address were actually used up long ago. The main reason why that hasn't brought the internet to a screeching halt is that various technical workarounds have been adopted. The best known is Network Address Translation (NAT), which allows a large number of users to access the internet via a shared IPv4 address.

By deploying NAT and other short-term fixes, we may have headed off the acute problem, but we've also shot ourselves in the foot. Most users don't actually have a proper internet connection of the kind envisaged by the net's designers. Without a unique IP address, your computer is unreachable for the outside world. And the arrival of Carrier-Grade NAT (CGNAT), a cascade of multiple NAT layers, has made things even worse.

STUN

As long as you initiate connections yourself (like your connections to web and mail servers), it doesn't matter that your computer isn't directly accessible from the internet. However, for real-time applications such as internet telephony (VoIP), instant messaging and multi-player gaming, users need to be able to exchange UDP data packages without any discernible delay. If either party doesn't support IPv6, interaction has to rely on IPv4. And, if you're on a NAT network, which almost all IPv4 users are, that's impossible without a special STUN server (Session Traversal Utilities for NAT). One of the clients uses the STUN server to establish its own external IP address/port number. The relevant application then shares that information with the other client using the session management/signalling protocol.

But, if both clients are on NAT networks, things quickly get very complicated: various NAT traversal strategies have to be used, depending on the forms of NAT separating the peers that want to communicate. As a user, the main thing you notice is that it's simply not possible to establish a good connection. Who hasn't experienced a VoIP or WebRTC session where someone has no picture or no sound, making proper interaction impossible? That happens when the necessary data links (which are usually based on RTP) can't be established.

TURN and ICE

In problem situations of the kind described, the ultimate solution is a TURN server (Traversal Using Relays around NAT). As the names suggests, that's a server that acts as a relay station between two peers. Multimedia data is sent to the TURN server by one client and picked up by the other. In other words, the problem of peers being unable to reach each other is resolved by linking them both to a separate internet server (which does have a unique IPv4 address, of course).

TURN has two big drawbacks: each connection needs its own resources (data buffers) on the server, and the relay station needs a lot of centralised bandwidth. It's therefore an expensive solution and not readily scalable. What's more, having an extra communication step causes delay, which is highly undesirable for real-time applications.

Finally, there's the ICE protocol (Interactive Connectivity Establishment), which was developed to minimise the need for a TURN server. With ICE, a sequence of methods and transmission addresses (IP addresses/port numbers) are tried in turn in an effort to connect the peers. Only if all else fails is the TURN server used.

Multi-player games

It's not surprising that Microsoft is an advocate of IPv6. The multi-player games on the company's Xbox consoles work fastest (and most cheaply) when players can communicate with each other directly, on the basis of IPv6. Having a relay station in the form of a TURN server impairs real-time interaction between players, and therefore spoils the game.