Hosting Glossary: Every Term Explained

A plain-English dictionary of the hosting, DNS, email and infrastructure terms that appear across KapsuleHost and this help centre.

Every entry is short on purpose. Where a term has a full guide of its own, the definition links to it, so you can read the one-line version here and the deep version there.

Domains and DNS

Domain name The address people type to reach you, like yourbusiness.co.nz. You lease it from a registry through a registrar for a fixed term, usually one year at a time. Kapsule is a registrar, so you can register, transfer and renew domains in the panel. See Adding and Connecting Your Domain and Domains.

Registrar The company that holds your domain registration on your behalf and can change its settings. If your domain is registered with Kapsule, we are your registrar. If it is registered elsewhere, that company is, and some changes (nameservers, transfer codes) have to be made there.

DNS (Domain Name System) The internet's address book. It turns a name like yourbusiness.co.nz into the numeric IP address of the machine that answers for it. Nothing on the internet finds you without it. See DNS Basics.

Nameserver A server that holds the authoritative answers for your domain's DNS. Kapsule runs four: ns1.kapsulecloud.com, ns2.kapsulecloud.com, ns3.kapsuledns.com and ns4.kapsuledns.com. Pointing your domain at those four is what puts your DNS under Kapsule's control. See Nameservers.

DNS zone The full set of records for one domain. When you open the DNS tab for a domain in the panel, you are editing its zone.

A record Maps a name to an IPv4 address. yourbusiness.co.nz -> 203.0.113.10. This is the record that sends web visitors to your site.

AAAA record The same idea as an A record, but for an IPv6 address.

CNAME record An alias. It says "this name is really that other name, go look that up instead". Common for www. A CNAME cannot sit on the bare domain (the apex) alongside other records, which is why the apex uses an A record or an ALIAS. See CNAME Records.

ALIAS record A CNAME-like record that our DNS is allowed to place on the apex of a domain, because it resolves the target and answers with an address rather than a redirect. Enabling the Kapsule CDN uses one.

MX record Says which mail server accepts email for the domain, with a priority number (lower wins). Get this wrong and inbound email stops. See MX Records.

TXT record Free-form text attached to a name. Used for almost every kind of proof or policy: SPF, DKIM, DMARC, and domain-ownership verification for third-party services. See Domain Verification Records.

SRV record Advertises the host and port for a specific service, used by things like autodiscover and chat protocols.

CAA record Lists which certificate authorities are allowed to issue certificates for your domain. A wrong CAA record blocks certificate issuance.

TTL (time to live) How many seconds a resolver is allowed to cache an answer before asking again. A 3600 TTL means a change can take up to an hour to be seen by someone who already looked the name up. Lower the TTL before a planned change, then raise it afterwards.

Propagation The informal name for the waiting period after a DNS change, while caches around the world expire and pick up the new answer. Our nameservers update within seconds. What you are waiting on is everyone else's cache, which is why the advice is usually "up to 24 to 48 hours" even though it is normally far quicker.

Resolver The DNS server your device or network actually asks. Your ISP runs one; so do public services. Resolvers cache, which is why you and a friend can see different answers for a few hours after a change.

DNSSEC A cryptographic signature over your DNS answers, so a resolver can tell that nobody tampered with them in transit. Kapsule supports it, and it is a real switch with a real risk: unsign in the wrong order and your domain goes dark. See DNSSEC.

Glue record An address record for a nameserver that lives inside the domain it serves, published at the registry to break the circular lookup. Only relevant if you run your own nameservers on your own domain. See Glue Records.

Subdomain A name under your domain, like shop.yourbusiness.co.nz. It is just another record in the same zone. See Subdomains and Parked Domains.

WHOIS The public registration record for a domain: who holds it, when it expires, which registrar. Privacy services replace the contact details with a proxy where the registry allows it. See WHOIS Privacy.

EPP code Also called an auth code or transfer code. A per-domain password that authorises a transfer to another registrar. See EPP Auth Codes.

Web and Security

SSL / TLS The encryption layer that protects traffic between a browser and your site. TLS is the current protocol; "SSL" is the old name that stuck. A certificate proves your server really is the one for that domain. See SSL Certificates.

HTTPS HTTP carried over TLS. The padlock in the address bar. Every Kapsule site should be served over HTTPS.

Certificate authority The organisation that issues and vouches for TLS certificates. Issuance normally requires proving control of the domain, which is why DNS has to be correct before a certificate can be issued.

Mixed content An HTTPS page that pulls an image, script or stylesheet over plain HTTP. Browsers block or warn on it, and the padlock breaks. See Fixing Mixed Content.

CDN (content delivery network) A network of caching servers spread around the world, so a visitor in London is served from a nearby machine instead of pulling everything from the origin. Kapsule has two tiers, Kapsule CDN and Kapsule CDN+, and they are gated by plan. See Enabling the CDN.

Edge Shorthand for those distributed caching servers, and for code that runs on them rather than at the origin. "Served from the edge" means the visitor never touched your hosting server.

Origin The real server your content lives on, behind any CDN or proxy. When the edge does not have a cached copy, it fetches from the origin.

Cache A stored copy of something expensive to produce, kept so the next request is fast. There are several layers: the browser's, the CDN's, a page cache on the server, an object cache in front of the database, and PHP's own opcode cache. Clearing one does not clear the others. See Purging the CDN Cache and Site Caching.

Purge Explicitly throwing away cached copies so the next request rebuilds from the origin. What you do after publishing a change that visitors still cannot see.

WAF (web application firewall) A filter in front of your site that inspects requests and blocks ones matching known attack patterns. It is why a legitimate but unusual request occasionally gets a 403.

Rate limit A cap on how many requests one client can make in a window. Protects a site from being hammered; also the reason a badly behaved script gets cut off.

Two-factor authentication (2FA) A second proof of identity at login, on top of your password, usually a rotating code from an app. See Two-Factor Authentication.

Servers and Hosting

Shared hosting Many customers' sites on one machine, isolated from each other, sharing its resources. The Kapsule web hosting plans work this way, and it is the right answer for most sites.

vCPU (virtual CPU) One CPU thread presented to your virtual machine. On a shared vCPU tier that thread is shared with other tenants and can be contended. On a dedicated vCPU tier the physical core is yours alone, so performance does not depend on what the neighbours are doing. See Choosing an Architecture.

ARM vs x86 Two different CPU instruction sets. x86 is the long-standing standard and runs essentially everything. ARM is newer in the server world and usually cheaper per unit of performance, but any software you install must have an ARM build, and some commercial or legacy binaries do not. If you are unsure, choose x86. Kapsule ARM tiers are Photon, Quark, Lepton and Muon; the Standard x86 tiers are Meteor, Comet, Atlas, Apollo, Vega and Pulsar. See Choosing an Architecture.

Managed vs unmanaged On an unmanaged server you own the operating system, updates, and everything above them. On a managed server Kapsule looks after the platform layer for you. Every Kapsule server tier is orderable either way. See Managed vs Unmanaged.

Dedicated server A whole physical machine, not a slice of one. No neighbours at all. Carries a one-time setup fee. See Dedicated Servers.

Region The physical location a server runs in. It sets latency for your visitors and can matter for data residency.

Uptime The percentage of time a service was reachable, measured over a period. 99.9% over 30 days is about 43 minutes of downtime. See Status and Uptime.

Egress Data leaving the platform towards the internet: your visitors' downloads, your backups being pulled out. Some providers bill it. Kapsule Storage Servers (Shelf, Trench, Abyss) have no egress fees.

Snapshot A point-in-time image of a whole server's disk, taken by the platform and restorable as a unit. Good for "I am about to do something risky". See Server Snapshots.

Backup A copy of your data kept somewhere else, on a schedule, so you can recover after a mistake or a failure. Kapsule takes automatic daily backups retained for 30 days, with longer retention available as an add-on. A snapshot is not a substitute for a backup. See Taking a Backup and Restoring From a Backup.

Point-in-time recovery (PITR) Restoring to an arbitrary moment rather than to whichever nightly backup happens to exist, which limits how much work a bad change can cost you. See Point-in-Time Recovery.

Staging A second, private copy of your site where you can test changes before they reach real visitors, then push the good ones live. See Staging Environments.

Applications and Access

PHP The programming language WordPress, WooCommerce and most classic web software are written in. Its version matters: newer versions are faster and supported for longer, but very old plugins can break on them. See Changing PHP Version.

PHP extension An optional module that adds capability to PHP, such as image processing or a database driver. Software often lists required extensions in its install docs. See PHP Extensions and Settings.

php.ini / .user.ini The configuration files that set PHP's limits, such as how much memory a script may use and how large an upload may be. See PHP Extensions and Settings.

Database Structured storage that your application reads and writes. A WordPress site keeps its posts, pages, users and settings in one. Losing it loses the site, even if the files survive. See Remote Database Access.

phpMyAdmin A web interface for browsing and editing a database directly. Powerful and unforgiving. See Using phpMyAdmin.

SFTP Secure file transfer, run over an SSH connection. What you use to upload and download your site's files with a desktop client. See SFTP Access.

SSH An encrypted remote connection to a server. It gives you a command line rather than a file browser, and it is also the tunnel that SFTP and secure database connections travel through. Access is by key, not password. See Adding SSH Keys.

SSH key A pair of files: a private key you keep and never share, and a public key you give to the server. The server proves you hold the private one without it ever crossing the wire.

Cron job A command the server runs automatically on a schedule. Used for scheduled publishing, imports, cleanups and reports. See Cron Jobs.

Git The version-control system almost all modern development uses. Kapsule can deploy a site straight from a Git repository. See Git Deploy and Orbit.

Environment variable A named value handed to your application at runtime, usually for configuration and secrets, so they are not written into the code. See Environment Variables.

Build The step that turns your source code into the files that actually get served. Modern frameworks need one; a plain HTML site or a WordPress site does not.

Email

Mailbox An actual account with storage that receives and holds mail, and that you can log into. See Setting Up Your Mailbox.

Alias An extra address that delivers into an existing mailbox. No separate storage, no separate login. Cheaper than a mailbox and usually what you want for info@. See Email Aliases.

Forwarder A rule that sends mail arriving at one address on to another address, often at a different provider. See Email Forwarding.

Catch-all A rule that accepts mail for any address at your domain that does not otherwise exist. Convenient, and a magnet for spam. See Catch-All Addresses.

IMAP A mail access protocol that keeps messages on the server and syncs every device to the same state. The right choice in almost every case. See IMAP vs POP3.

POP3 The older protocol, which downloads mail to one device and traditionally removes it from the server. Use it only if you have a specific reason.

SMTP The protocol used to send mail, as opposed to reading it. Your mail client uses it to hand outgoing messages to the server.

SPF A TXT record listing which servers are allowed to send mail for your domain. Receivers check it. See SPF, DKIM and DMARC.

DKIM A cryptographic signature added to each outgoing message, with the public key published in DNS, so a receiver can verify the message really came from your domain and was not altered.

DMARC A TXT record telling receivers what to do when SPF and DKIM fail, and where to send reports. The policy that makes the other two enforceable.

Bounce A delivery failure returned by the receiving server, with a code explaining why. Hard bounces mean the address is bad; soft bounces are temporary. See Bounce Codes.

Blacklist / blocklist A published list of IP addresses or domains that a receiver may refuse mail from. Being listed is usually a symptom of compromise or bad sending practice. See Blacklist Delisting.

Money and Account Terms

Plan The package you subscribe to, which sets your resources and which features are available. See Upgrading Your Plan.

Add-on An extra purchased alongside a plan, such as longer backup retention or an additional IPv4 address. See Store Add-Ons.

Proration Charging only for the part of a billing period you actually use, which is how a mid-cycle upgrade is priced. See Proration.

Renewal The automatic charge that extends a subscription or a domain for another term. See Renewals and Auto-Renew.

GST New Zealand goods and services tax, 15%. Catalogue and panel prices are shown excluding GST. It is added at checkout when your account currency is NZD. See GST and Tax Invoices.

Setup fee A one-time charge on first order, separate from the recurring price. Dedicated, Storage and GPU servers carry one. Standard cloud server tiers do not.

Where to Go Next

If a term here sent you looking for more, the hub articles are the fastest way in: