Glossary

Glossary of terms

Domains, DNS records, mail, and SSL in plain language — no jargon where it can be avoided.

Domains and registration

Domain: A unique name in the domain name system that identifies a site, mail, or other service on the internet — for example, example.com.ua.
Zone: A part of the domain namespace under a given suffix, administered by its own registry — for example, .com.ua or .ua.
Registry: The organisation that keeps the database of all domains in a given zone and has the final say on whether a domain is free.
Registrar: A company accredited by a registry to register domains on behalf of customers — such as ZRAZU.
Registrant: The domain owner: the person or organisation the domain is registered to.
Trademark: A registered mark for goods and services; a second-level .ua domain requires a trademark certificate or an international registration protected in Ukraine.
gTLD, ccTLD: gTLD — generic top-level domains (.com, .shop); ccTLD — country-code domains (.ua, .de).
IDN, Punycode: IDN allows domains with Cyrillic or other non-Latin characters; Punycode is the technical Latin-script encoding of such a name (xn--…) that every server understands.

DNS: The Domain Name System: a distributed database that turns a domain into an IP address and other technical data.
NS (nameserver): A server that stores and serves a zone’s DNS records; a domain’s NS records determine who manages its DNS.
A record: A record pointing to a server’s IPv4 address — usually the one that shows where the site lives.
AAAA record: The same as an A record, but for an IPv6 address.
CNAME: An alias record: a domain or subdomain points to another name instead of a direct IP address. Not allowed on the root domain.
MX: A record that sets which server accepts mail for a domain; there can be several MX records with different priorities.
TXT: A free-form text record in the zone; often used to verify domain ownership and for SPF/DKIM/DMARC.
TTL: The time in seconds a resolver may keep a record cached before asking again.
DNSSEC: A DNS extension that cryptographically signs responses so they can’t be tampered with in transit.
WHOIS: A public protocol and service for checking who registered a domain, when, and when the registration expires.
RDAP: A modern replacement for WHOIS with structured data and clearer privacy rules.

SPF: A TXT record listing the servers allowed to send mail on behalf of a domain.
DKIM: A digital signature on an email that confirms it wasn’t altered in transit and really was sent by the domain owner.
DMARC: A policy telling mail servers what to do with a message that fails SPF or DKIM, and where to send reports.

SSL/TLS: Protocols that encrypt the connection between a browser and a site; SSL is the older name — today it’s actually TLS doing the work.
DV certificate: A Domain Validation certificate: confirms only that the applicant controls the domain. The encryption is the same as a free certificate’s.
OV certificate: An Organization Validation certificate: additionally confirms the site’s owning organisation; the details are visible in the certificate.
EV certificate: An Extended Validation certificate with the most thorough organisation check; in modern browsers it looks the same as DV or OV.
Wildcard certificate: A certificate that covers a domain and all its subdomains at one level at once (*.example.com.ua).
ACME: A protocol for automatically issuing and reissuing SSL certificates (for example, for Let’s Encrypt) with no manual steps.
Let’s Encrypt: Let’s Encrypt — a certificate authority that issues free DV certificates with automatic reissuing.

Transfer code (auth code): A secret code that confirms the domain owner is the one requesting the transfer to another registrar.
Transfer lock: A safeguard that blocks a domain transfer until the owner deliberately lifts it.
Grace period: The time after a registration expires when the domain still works and the owner can renew it on ordinary terms.
Redemption period: The time after the grace period when the domain no longer works but the owner can still recover it — usually at a higher cost.
Pending delete: The final short stage before a domain becomes free for anyone; it can no longer be recovered at this stage.

Technical definitions follow the relevant standards (RFCs); product terms are given as ZRAZU uses them.