# Glossary

## agent device

A machine approved by a person as an agent of their airdress, holding its
own keys, through the `airdress-agent` binary. It can write to the agent
bus and hold agent chat conversations. See [Agents](/agents/).

## Airdress

The platform and product name: one permanent address for your agents,
devices and services, wherever they run. Written with a capital A in prose.
In lower case, "an airdress" is one such address and everything behind it.

## airdress name

A claimed identifier in the form `myname.a.airdr.es` that routes internet
traffic to an airdress. Each name is globally unique and permanently bound
once claimed — names are never reclaimable, even after deletion.

See: [hub](#hub)

## anycast

A routing technique where the same IP address is announced from multiple
geographic locations. Traffic is delivered to the nearest announcing node,
providing low-latency access and automatic failover.

See: [BGP](#bgp), [VIP](#vip)

## BGP

Border Gateway Protocol. The routing protocol used by relay and DNS PoPs to
announce the anycast prefix to the internet. If a PoP becomes unhealthy,
its route is withdrawn and traffic shifts to the next-nearest PoP.

See: [relay PoP](#relay-pop), [DNS PoP](#dns-pop)

## DNS PoP

A Point of Presence running authoritative DNS for the `*.a.airdr.es` zone.
Record changes reach every DNS PoP within seconds. DNS PoPs serve at the
anycast VIP `185.43.32.1` (`ns1.airdr.es` and `ns2.airdr.es`).

See: [anycast](#anycast)

## enrollment

The process of admitting a device to an airdress, by a pairing code or QR
shown by the CLI or an app, or by a phone approving a request. See
[Devices, machines and homes](/cli/devices-and-machines/).

## federation

Communication between two airdresses' operators, each verifying the other's
signed identity.

See: [MLS](#mls), [operator](#operator)

## FQDN

Fully Qualified Domain Name. A complete domain name that specifies a host's
exact position in the DNS hierarchy, ending with a trailing dot. Example:
`myname.a.airdr.es.`

## hub

The Airdress account portal at [account.airdress.co](https://account.airdress.co).
Manages user accounts, airdress name claims, billing, and permissions.

See: [airdress name](#airdress-name)

## machine

A computer approved to act on an airdress with its own key, such as a shell
host, a CI runner or a Home Assistant. Admitted by a person comparing the
fingerprint or confirmation code the machine printed.

See: [shell host](#shell-host)

## mini-app

A ZIP-bundled static web application served by the operator under a subdomain.
Mini-apps are distributed through the mini-app registry at
[miniapps.airdress.co](https://miniapps.airdress.co).

See: [plugin](#plugin), [operator](#operator)

## MLS

Messaging Layer Security, defined in RFC 9420. A protocol for end-to-end
encrypted group messaging used by Airdress for chat functionality. Provides
forward secrecy and post-compromise security.

See: [federation](#federation)

## operator

The `airdress-operator` server that an airdress runs on. It holds the
airdress's certificate and terminates TLS, serves its API, and runs its
functions, plugins, shells and chat.

See: [relay](#relay)

[Operator CLI reference](/reference/cli/)

## plugin

A signed release that runs on an airdress: a form, a map, a small app on its
own subdomain. Distributed through the plugin registry at
[plugins.airdress.co](https://plugins.airdress.co). See
[Plugins](/cli/plugins/).

See: [mini-app](#mini-app), [operator](#operator)

## relay

The edge service that accepts IPv4 connections for airdress names on ports
443 and 80 and passes them through to the right airdress without
decrypting them: by TLS server name (SNI) on 443, by `Host` header on 80.

See: [relay PoP](#relay-pop)

## relay PoP

A Point of Presence running the relay. Relay PoPs in Frankfurt, Amsterdam,
Newark and Los Angeles announce `23.163.148.0/24` and serve at the VIP
`23.163.148.11` (`relay.airdress.co`). A PoP that fails its health check
withdraws its route.

See: [relay](#relay), [anycast](#anycast), [VIP](#vip)

## shell host

A Linux machine running `airdress shell host`, approved as a machine of
your airdress, on which your devices open terminals by profile. See
[Shells](/shells/).

## VIP

Virtual IP address. The anycast IP that clients connect to: `23.163.148.11`
for the relay and `185.43.32.1` for DNS, each announced from every active
PoP via BGP. See the
[IP ranges](https://airdress.co/ips) for current prefixes.

See: [anycast](#anycast), [BGP](#bgp)

## zone cut

The DNS delegation point where `a.airdr.es` is delegated from the parent
zone to the Airdress DNS PoPs. All airdress names exist below this
delegation as subdomains of `a.airdr.es`.

See: [DNS PoP](#dns-pop), [airdress name](#airdress-name)