Three parts, three jobs
| Part | What it is | If it fails |
|---|---|---|
| Domain name | The name, rented from a registrar for a set term | Nothing resolves once it lapses |
| DNS | The records that map the name to servers | The name points nowhere, or to the wrong server |
| Hosting | The server that stores and sends the site | The name resolves, but nothing answers |
The split matters when something breaks or when you switch providers. A site can be down because the domain expired, because a DNS record points to an old server, or because the server itself is down, and each has a different fix. The checks in is the website down or just me go through them in order.
The domain: a registration, not a purchase
Three parties are involved in every domain. The registrant is you. The registrar is the company you pay; ICANN describes an accredited registrar as an entity that offers domain name registration services to registrants. The registry runs the top-level domain itself, such as .com or .org, and keeps the master list of names in it. ICANN sits above them: it draws up contracts with each registry and runs the accreditation system for registrars. It does not control what you put on your site.
You do not buy a name outright. ICANN's renewal FAQ says a registration is for a set period, typically one to ten years, and you keep it by renewing through your registrar. ICANN policy requires registrars to send two renewal reminders. As a registrant you must keep your contact details accurate for directories such as WHOIS and answer your registrar's inquiries within 15 days. The WHOIS lookup shows a domain's registrar, creation date and expiry date. What happens after an expiry date passes is laid out step by step in what happens when a domain expires.
There are many endings to choose from. IANA's list of top-level domains had 1,436 entries on October 30, 2026. The guide on choosing a domain extension compares them.
DNS: the records that connect name and server
DNS is a distributed lookup. At the top sits the root zone, which IANA manages; it says which name servers are responsible for each top-level domain. IANA lists the root servers as 13 named authorities, a.root-servers.net through m.root-servers.net, which in reality are hundreds of servers in many countries. The .com servers in turn know which name servers hold the records for example.com, and those answer the actual question.
The records for your domain live in a zone at your DNS provider, which is often the registrar or the host. These are the ones you will edit:
| Type | No. | Holds | Example value |
|---|---|---|---|
| A | 1 | An IPv4 address | 203.0.113.10 |
| AAAA | 28 | An IPv6 address | 2001:db8::10 |
| CNAME | 5 | The canonical name this name is an alias for | shop.example.net. |
| MX | 15 | A mail server, with a preference (lower wins) | 10 mail.example.com. |
| TXT | 16 | Text strings, used for verification and mail rules | "v=spf1 -all" |
| NS | 2 | An authoritative name server for the zone | ns1.dnshost.example. |
Three rules from the RFCs explain common setup errors. First, RFC 1034 says that if a CNAME is present at a name, no other data should be present. That is why the bare domain, which must carry NS records, cannot simply be a CNAME, and why hosts give you A and AAAA addresses for it instead. Second, MX records carry a preference number, and RFC 1035 says lower values are preferred, so 10 mail1 is tried before 20 mail2. Third, every label between dots can be at most 63 octets and a whole name at most 255.
TXT records do a lot of quiet work: proof that you control a domain, such as the DNS record Search Console checks for a Domain property, and the SPF and DMARC rules that the SPF, DKIM and DMARC guide explains. The DNS lookup shows every record a domain publishes, with its TTL.
TTL: why changes take time
Every record has a TTL. RFC 1035 defines it as the time interval, in seconds, that a record may be cached before it should be discarded. Resolvers at internet providers and in offices may keep answers that long. After you change a record, anyone whose resolver fetched the old one just before can keep getting it until the TTL runs out:
| TTL | Old answer may live for up to |
|---|---|
| 300 | 5 minutes |
| 3,600 | 1 hour |
| 14,400 | 4 hours |
| 86,400 | 1 day |
So the trick for a planned move is to lower the TTL to 5 minutes at least one old TTL before the switch. If the record had 86,400, lower it a day ahead. On moving day the change then spreads within minutes, and afterwards you can raise the TTL again.
Hosting: the server that answers
Hosting is the computer that holds the files or runs the application and answers requests on ports 80 and 443; the guide to common port numbers explains those. Hosting ranges from free plans for static sites to managed servers. The free website hosting list compares free plans, and the free website builders list covers builders with a free plan. A CDN can sit in front of any host to answer from servers near your visitors.
The website cost calculator adds up what the parts cost together: the domain renewal every year, the hosting plan, and everything else a site needs.
Worked example: switching hosts, keeping the domain
A site at example.com runs on host A. The domain is registered at a registrar, which also runs the DNS. The owner moves to host B:
- Look up the current records with the DNS lookup and note the TTL of the A record, say 14,400 seconds, 4 hours.
- At least 4 hours before the move, lower that TTL to 300.
- Copy the site to host B and test it there, using a temporary address if host B provides one.
- Change the A record, and AAAA if there is one, to host B's addresses. Leave MX and TXT records alone, or mail stops.
- Keep host A running for a day or two while the last cached answers expire, then cancel it.
- Raise the TTL back to its old value.
The domain never moved; only one DNS record changed. Moving the domain itself to another registrar is a separate step, and changing the domain name is a site move of its own, covered in how to move a website to a new domain.
Frequently asked questions
What is the difference between a domain and hosting?
The domain is the name people type, such as example.com, registered through a registrar for a term of usually one to ten years. Hosting is the server that stores the website and sends it to visitors. DNS connects the two: its records tell browsers which server answers for the name. You can buy all three from one company or each from a different one.
Do I own my domain name?
You hold a registration for a set period, which ICANN says is typically one to ten years, and you keep it by renewing. If you do not renew, the name can eventually be released and registered by someone else. ICANN also requires registrants to keep their contact information accurate.
How long does a DNS change take?
As long as the old record's TTL, in most cases. RFC 1035 defines the TTL as the time in seconds a record may be cached before it should be discarded. With a TTL of 3600, resolvers that fetched the old record just before your change can keep using it for up to an hour. Lower the TTL a day ahead of a planned move, then raise it again afterwards.
Can I point my domain at a different host without moving the domain?
Yes. The registration stays with your registrar; you only change the DNS records, usually the A and AAAA records or a CNAME, to the new host's addresses. If the new host also runs your DNS, you change the NS records at the registrar instead.
What is a registrar and what is a registry?
A registrar is the company you buy the domain from; ICANN calls an accredited registrar an entity that offers domain registration services to registrants. A registry runs a whole top-level domain such as .com and keeps its master list. ICANN draws up contracts with each registry and runs the accreditation system for registrars.
Sources
- ICANN: What does ICANN do? (coordinates the internet's unique identifiers; contracts with each registry; accreditation system for registrars; does not control content)
- ICANN: Information for registrars and registrants (an accredited registrar offers domain name registration services to registrants; a registrant is an individual or entity registering a name in a generic TLD)
- ICANN: Domain name renewal and expiration FAQs (registration typically for one to ten years; renew through your registrar; two renewal reminders required; names not renewed can be released)
- ICANN: Registrant benefits and responsibilities (accurate information for WHOIS; respond to registrar inquiries within 15 days; keep payment details current for auto-renewal)
- IANA: Root servers (13 named authorities, a to m, operated by 12 organizations, as hundreds of servers worldwide) and the Root Zone Database (IANA manages the DNS root zone and its TLD delegations)
- IANA: list of top-level domains, version 2026103000 (1,436 entries on October 30, 2026)
- RFC 1035, Domain names: implementation and specification (record types A, NS, CNAME, MX, TXT and their numbers; TTL is the time in seconds a record may be cached; MX preference, lower values preferred; labels up to 63 octets, names up to 255)
- RFC 1034, Domain names: concepts and facilities, section 3.6.2 (if a CNAME is present at a node, no other data should be present)
- RFC 3596, DNS extensions to support IPv6 (the AAAA record holds one IPv6 address, type 28)