vacuum-wall/docs/architecture.md

Architecture

Request Flow

The following describes the path a request takes from an external client to a backend service and back:

Proxied Service (e.g., app.example.com)

1. An external client sends an HTTP request to app.example.com.
2. The request arrives at the Vacuum Wall host's WAN interface, assigned to the external firewalld zone. A firewall rule allows inbound traffic on port 443 (HTTPS).
3. nginx, listening on port 443, terminates the TLS connection using the domain's certificate.
4. nginx evaluates the server_name against the configured server blocks. The matching block is generated from the domain entry in config/nginx/config.json.
5. The request is forwarded to the backend service (e.g., 192.168.2.50:8080) via an proxy_pass directive.
6. The backend service processes the request and returns an HTTP response.
7. nginx adds security headers (X-Content-Type-Options, X-Frame-Options, HSTS, etc.) to the response.
8. nginx encrypts the response with TLS and sends it back to the client through the WAN interface.

For HTTP requests (port 80), nginx returns a 301 redirect to the HTTPS equivalent before any proxying occurs.

Management WebUI Access (e.g., <hostname>.local)

1. A client sends an HTTPS request to the management domain.
2. nginx terminates TLS and proxies the request to 127.0.0.1:9090 where the Flask WebUI is listening. No nginx-level authentication is applied.
3. Flask validates the JWT from the Authorization: Bearer <token> header, checks the token against the SQLite blacklist (data/auth.db), and verifies per-subsystem permissions before processing the request. Public endpoints (login, WebAuthn authenticate) are exempt from validation.
4. The Flask application communicates with the vacuum-walld daemon via a Unix socket (data/daemon.sock) for any privileged operations.
5. The daemon executes the privileged commands via the sudo whitelist and returns structured results.
6. Flask renders an HTML or JSON response, which nginx returns to the client over the encrypted connection.

Because Flask binds only to 127.0.0.1, it is unreachable directly from any external interface. The nginx reverse proxy is the sole entry point.

Subsystem Communication

The following diagram summarizes how the Flask WebUI communicates with each managed subsystem:

External Client ──→ nginx (SSL termination, NO auth) ──→ Flask WebUI (127.0.0.1:9090, JWT + permission check)
Flask WebUI ──→ daemon/client.py (path resolution, Unix socket) ──→ vacuum-walld (aiohttp server)
Flask WebUI ──→ lib/db.py (abstract DB interface) ──→ SQLite (data/auth.db)
vacuum-walld ──→ daemon/handlers/auth.py ──→ lib/auth.py ──→ JWT operations
vacuum-walld ──→ daemon/handlers/firewall.py ──→ sudo firewall-cmd ──→ firewalld / D-Bus ──→ nftables
vacuum-walld ──→ daemon/handlers/nginx.py ──→ write local .conf files ──→ sudo cp to /etc/nginx/ ──→ sudo nginx -t && sudo nginx -s reload
vacuum-walld ──→ daemon/handlers/dnsmasq.py ──→ render config ──→ sudo cp /tmp/... /etc/dnsmasq.d/vacuum-wall.conf ──→ sudo systemctl restart dnsmasq
vacuum-walld ──→ daemon/handlers/acme.py ──→ acme.sh (subprocess) ──→ deploy hook (daemon API) ──→ ACME provider
vacuum-walld ──→ daemon/handlers/wireguard.py ──→ render data/wireguard/wg0.conf ──→ sudo cp to /etc/wireguard/ ──→ sudo wg-quick up wg0
vacuum-walld ──→ daemon/handlers/network.py ──→ render 50-<name>.network ──→ sudo cp to /etc/systemd/network/ ──→ sudo networkctl reload
vacuum-walld ──→ daemon/handlers/logs.py ──→ sudo journalctl ──→ systemd journal

Two-User Model with Shared Group

Vacuum Wall uses two distinct system users bridged by a shared group:

• vacuum-walld (daemon user): Runs the privileged background daemon. Holds the NOPASSWD sudo whitelist for all system-level commands. Runs with NoNewPrivileges=yes (satisfiable since sudo is called directly by the daemon process).
• WebUI user (default: repo owner in --dev mode): Runs the Flask web serving process. Has zero sudo access. Communicates with the daemon via a Unix socket at data/daemon.sock. Runs with NoNewPrivileges=yes.
• Shared group: Both users share the WebUI user's primary group. The daemon socket is owned by vacuum-walld:<group> with mode 0660, allowing the web UI user to connect via group permission. The project directory is owned by the WebUI user with group-read+execute, giving the daemon read access to configs and shared files.

This design isolates privilege escalation entirely within the daemon, so a compromised Flask process cannot invoke sudo directly. The lib/ modules no longer contain sudo calls; all privileged command execution lives in daemon/handlers/*.py.

Dev mode variant: When scripts/install.sh --dev is used, the repo owner (e.g., wall) becomes the WebUI user. The project directory remains owned by the repo owner, preserving git operations and code editing. The daemon user (vacuum-walld) has the repo owner's primary group as its own primary group, granting read access to project files. All subdirectories carry the setgid bit (g+s) so new files inherit the group regardless of the creator's primary group.

The lib/ modules auto-discover the project root at runtime via Path(__file__).resolve().parent.parent. This works because scripts/install.sh performs an editable pip install (pip install -e .), keeping module files in the project directory rather than copying them to site-packages/.

JWT Token Model

Vacuum Wall uses JWT-based authentication with access/refresh token rotation. Tokens are stored in browser sessionStorage and injected as Authorization: Bearer <token> headers. The API never reads cookies — authentication is header-only.

Token	Lifetime	Storage	Purpose
Access	15 min	sessionStorage / memory	API auth, permission checks
Refresh	7 days	sessionStorage	Token rotation, new access tokens

JWT payload contains sub (username), exp (expiry), iat (issued at), jti (unique identifier), type ("access" or "refresh"), permissions (per-subsystem permissions), and session_id (session binding). Access tokens additionally contain permissions and session_id.

Each user has a unique signing secret stored in the users.jwt_secret database column (generated as a 32-byte base64url token via secrets.token_urlsafe(32)). This per-user secret model means tokens signed for one user cannot be validated as another user's tokens. Both Flask and daemon processes validate tokens by extracting sub from the unverified payload, looking up the user's secret, and verifying the signature with that secret. Expired and blacklisted tokens are rejected against the SQLite token_blacklist table (via data/auth.db).

Token auto-refresh occurs before expiry. On logout or password change, tokens are blacklisted in the SQLite token_blacklist table to prevent reuse. The blacklist is cleaned of expired entries on every refresh operation.

Permission Model

Each user has per-subsystem permissions with two levels:

• "read" — GET /api/<subsystem>/* allowed; POST/PATCH/DELETE rejected with 403
• "rw" — all HTTP methods allowed for the subsystem

Flask before_request middleware enforces permissions by extracting the subsystem name from the blueprint route prefix (e.g., /api/firewall/ → "firewall"). The middleware checks request.user.permissions[subsystem]. If the permission level doesn't match the required level, a 403 response is returned.

The auth subsystem controls user management. User CRUD endpoints (/api/auth/users/*) require auth: "rw" ("admin required").

Login-related endpoints are public (no JWT required): POST /api/auth/login, POST /api/auth/webauthn/authenticate-begin, POST /api/auth/webauthn/authenticate-finish.

Database Layer

Vacuum Wall uses SQLite for authentication and user management data. Subsystem configuration remains as JSON in config/*/.

Architecture:

• lib/db.py — Query ID constants + abstract Database baseclass (no SQL strings)
• lib/db_sqlite.py — QUERY_MAP (query_id → SQLite SQL) + concrete implementation
• Subsystems call by query ID only — never write SQL

The abstract Database baseclass provides:

• Connection caching via self.conn property (lazy initialization)
• Prepared statement auto-cache (cached on first use, reused subsequently)
• query(query_id, params) — returns row dicts
• run(query_id, params) — returns rowcount
• run_one(query_id, params) — returns last_insert_id
• in_transaction() context manager — provides BEGIN/COMMIT/ROLLBACK with auto-commit suppressed inside

Environment variables (not config files) control database access:

Env Var	Default	Description
VACUUM_WALL_DB_BACKEND	sqlite	Database backend selection
VACUUM_WALL_DB_PATH	data/auth.db	SQLite database file path

Both Flask (webui/server.py) and daemon (daemon/server.py) call get_db() at startup. Each process opens its own connection to the same DB file. SQLite WAL mode enables concurrent reads; writes are serialized by SQLite.

Install-Time Templating

System configuration files in system/ are Jinja2 templates rendered by scripts/install.sh at install time:

• systemd/vacuum-wall.service, systemd/vacuum-walld.service, systemd/vacuum-wall-acme.service — {{ USER_NAME }}, {{ USER_DAEMON_NAME }}, {{ USER_GROUP }}, {{ PROJECT_DIR }}, {{ ACME_HOME }} are substituted to produce the final systemd unit files installed to /etc/systemd/system/. The PROJECT_DIR template variable is set from the INSTALL_DIR environment variable (defaults to the repo root).
• sudoers.d/vacuum-walld — {{ USER_DAEMON_NAME }} is substituted to produce the sudoers whitelist for the daemon user.
• The timer file (vacuum-wall-acme.timer) contains no variable paths and is installed as-is.

Runtime templates (system/nginx/*.conf, system/dnsmasq.conf, system/wireguard*.conf) are rendered at runtime by lib/ modules via Jinja2 with Python data.

State Management

Vacuum Wall uses a declarative configuration model. Persistent user-facing configuration lives in config/<subsystem>/config.json. Runtime artifacts and generated files live in data/<subsystem>/. The application renders these declarations into the format expected by the underlying system service.

Subsystem	Declarative Config	Runtime Data	Rendered Target	State Persistence
firewalld	config/firewall/config.json	data/firewall/rules.json	N/A (commands issued directly to firewalld via D-Bus)	firewalld manages its own persistent state in /etc/firewalld/. config.json is the declarative source of truth. rules.json serves as an automated backup snapshot.
dnsmasq	config/dnsmasq/config.json	data/dnsmasq/fragments/	/etc/dnsmasq.d/vacuum-wall.conf	The JSON file is the source of truth. The rendered .conf file is overwritten on each apply.
nginx	config/nginx/config.json	data/nginx/.htpasswd, data/nginx/sites-enabled/	data/nginx/sites-enabled/<domain>.conf + /etc/nginx/conf.d/vacuum-wall.conf	All proxy and management domain definitions are derived from the JSON config. Generated .conf files are overwritten on each apply.
WireGuard	config/wireguard/config.json	data/wireguard/	/etc/wireguard/wg0.conf	The JSON file defines the interface and all peers. The rendered WireGuard config is overwritten on each apply.
networkd	config/network/config.json	data/networkd/	/etc/systemd/network/50-<name>.network	The JSON file defines per-interface static addresses, routes, DNS, DHCP, and link settings. Each entry renders to a 50-<name>.network INI file. Stale files are cleaned on apply. Public DNS servers are auto-synced to dnsmasq upstreams.
ACME	config/acme/config.json	data/acme/	Certificate and key files	acme.sh manages its own state, renewal scheduling, and account keys. Vacuum Wall triggers issuance and renewal but does not maintain independent ACME state. Account registration (email, CA provider) is stored in the declarative config.

Background Polling

The daemon runs background polling tasks for subsystems with external runtime state. Each subsystem has a configurable interval and a two-layer diff (structural vs volatile) to minimize unnecessary broadcasts.

Subsystem	Interval	Rationale
firewall	30s	Most expensive collector (6+ subprocess calls)
wireguard	10s	Peer connections/handshakes change frequently
dnsmasq	10s	Lease file + service status
networkd	10s	Interface up/down, DHCP address changes

nginx, acme, and auth are not polled — they have no external runtime state.

Two-layer diff: Each poll cycle classifies changes as:

• Structural change (zones added, peers removed, config changed): triggers bump() + broadcast {"type": "versions", ...} → full UI re-load
• Volatile change only (transfer counters, DHCP-assigned IPs): sends {"type": "tick", "subsystems": [...]} → lightweight per-subsystem re-fetch
• No change: silence

Volatile fields per subsystem: wireguard (peer transfer/handshake stats), firewall (DHCP-assigned IPs), networkd (DHCP addresses, link metrics). Defined per collector via register_volatile().

Poll intervals are configurable via VACUUM_WALL_POLL_INTERVALS env var (firewall:30,wireguard:10,...).

On collector failure during a poll, no broadcast is sent (avoids noisy ticks). State data is set to None.

System Config Import

On daemon startup, lib/system_import.py reconciles live system configurations with the declarative JSON configs. This ensures that configurations created by scripts/install.sh or edited manually in system files are imported into the JSON source of truth, preventing drift.

When vacuum-walld starts, it calls import_all() which runs each subsystem import function:

• import_dnsmasq: Parses /etc/dnsmasq.d/vacuum-wall.conf (managed block between comment markers) → config/dnsmasq/config.json. Only writes if config doesn't exist or differs.
• import_wireguard: Parses /etc/wireguard/wg0.conf → config/wireguard/config.json. Skips if configs match.
• import_networkd: Parses /etc/systemd/network/99-*.network files (install-time files) → config/network/config.json. Only adds/updates interfaces; doesn't remove interfaces without a file (they may be pending apply).
• import_nginx: Parses data/nginx/sites-enabled/*.conf → config/nginx/config.json. Only touches vacuum-wall-managed files (identified by # Auto-generated by Vacuum Wall header). Skips _acme-challenge.conf.
• import_firewall: Runs sudo firewall-cmd --list-all-zones → config/firewall/config.json. Only writes if no config file exists (firewalld state always takes precedence).

Import failures are silently logged as warnings — they never abort daemon startup. The returned list of updated subsystems is logged for debugging.

Cross-Subsystem Sync Event Bus

When a subsystem's configuration changes, related subsystems are automatically updated to stay consistent. An in-process event bus (lib/sync.py) decouples subsystems — no handler calls into another handler's logic directly.

How It Works

1. A mutation handler saves its config (e.g., adding a DHCP range).
2. The handler emits a SyncEvent on the event bus.
3. Subscribers react by updating related subsystem configs:
   • DnsToFirewallSync: Adds dhcp, dns services to the firewall zone for each interface serving a DHCP range. Back-propagates gateway (interface IP) into DHCP ranges so clients receive their default route.
   • WgToFirewallSync: Creates or updates a vpn firewall zone with WireGuard interface, masquerade, UDP 51820 rich rule, and inter-zone accept rules for each peer's allowed_ips subnets. Cleans up WireGuard-created entries when no active peers exist.
   • FirewallToDhcpSync: Removes stale DHCP ranges for interfaces no longer in any zone. Ensures DHCP ranges on masquerade-enabled zones carry the gateway (interface IP). Logs warnings for zones with dhcp service but no range.
   • NetworkToAllSync: Suggests DHCP ranges for static-IP interfaces without ranges. Syncs firewall zone interface assignments — adding new interfaces and removing stale ones no longer in network config.
4. The handler refreshes state for the originating subsystem plus all transitively affected subsystems.

Guard Rails

• Idempotency: Each subscriber reads current state, computes desired state, writes the diff. Running twice is safe.
• No loops: The event bus tracks (subsystem, action) per dispatch cycle. Re-entrant emits for the same key are silently dropped.
• Firewall-cmd separation: Sync subscribers only write JSON config. They do NOT call firewall-cmd. The user clicks "Apply" on the firewall page to push to firewalld.
• Error handling: Subscriber exceptions are caught, logged as warnings, and do NOT abort the originating handler.

Frontend Impact

Minimal. The sync happens transparently in the backend. The "pending changes" indicator on the firewall page will show pending when DHCP or WireGuard saves (since sync writes JSON but does not call firewall-cmd).

System Config Import

On daemon startup, vacuum-walld runs import_all() from lib/system_import.py to reconcile any drift between system configuration files and the declarative JSON configs. This is invoked from daemon/server.py during initialization.

Each subsystem import function parses the corresponding live system config and updates the JSON config if they differ:

Subsystem	Source	Condition
dnsmasq	/etc/dnsmasq.d/vacuum-wall.conf	Always — parses managed block between markers
firewall	firewall-cmd --list-all-zones	Only if no JSON config exists yet
WireGuard	/etc/wireguard/wg0.conf	Always — parses INI format
networkd	/etc/systemd/network/99-*.network	Always — parses INI files
nginx	data/nginx/sites-enabled/*.conf	Always — parses generated server blocks

All imports are idempotent and non-destructive: they only write when configs differ, skip on failure (logged as warnings), and never abort daemon startup. This ensures that manual edits to system files (e.g., during install or troubleshooting) are reconciled into the declarative JSON source of truth.

Directory Structure

Config — Declarative Settings

Config files are persistent, user-editable JSON that defines the desired state for each subsystem:

config/
├── auth/
│   └── config.json                   # JWT settings, WebAuthn RP configuration
├── dnsmasq/
│   └── config.json                   # DHCP ranges, static leases, DNS forwarding, custom records
├── firewall/
│   └── config.json                   # Firewall zones, rich rules, forward ports
├── nginx/
│   └── config.json                   # Proxy domain definitions, management domain, SSL settings
└── wireguard/
    └── config.json                   # WireGuard interface and peer configuration
├── network/
│   └── config.json                   # Per-interface static IP, routes, DNS, DHCP settings

Data — Runtime Artifacts

The data/ directory holds generated files, credentials, and subsystem artifacts:

data/
├── auth.db                          # SQLite database: users, permissions, token_blacklist, webauthn_creds
├── nginx/
│   ├── .htpasswd                     # HTTP Basic credentials for basic-authed proxy domains (created on demand; the management UI itself uses JWT only)
│   └── sites-enabled/                # Generated nginx server block .conf files (one per domain)
├── dnsmasq/
│   └── fragments/                    # User-defined dnsmasq config fragments (appended verbatim)
├── firewall/
│   └── rules.json                    # Auto-generated firewall rule state backup
├── acme/                             # ACME certificate files (acme.sh home)
├── logs/
│   └── vacuum-wall.log              # Application log file
└── wireguard/                        # WireGuard runtime artifacts
├── networkd/                         # Generated 50-<name>.network files

Both config/ and data/ reside within the project directory. The systemd service unit's ReadWritePaths directive grants the processes write access to these directories, while keeping the rest of the filesystem read-only. The INSTALL_DIR value is templated into the service unit at install time.

The daemon uses a runtime directory at /run/vacuum-wall (created by systemd RuntimeDirectory=) for secure temporary files during config apply. tempfile.NamedTemporaryFile writes to this directory before sudo cp moves files to their final destination, eliminating TOCTOU symlink races that would exist with /tmp. The directory is automatically removed on service stop.

/run is a fresh tmpfs at every boot, so volatile runtime paths must be recreated at startup. This is a hard requirement, not a best practice: with ProtectSystem=strict, namespace setup fails (226/NAMESPACE) and the unit crash-loops if any ReadWritePaths= entry does not exist when the unit spawns. Each /run path the daemon references therefore needs a boot-time creator: the unit's RuntimeDirectory=vacuum-wall nginx covers the daemon-owned directories, and the system/tmpfiles.d/vacuum-wall.conf spec (installed to /etc/tmpfiles.d/) pre-creates /run/firewalld at early boot via systemd-tmpfiles-setup.service (in practice firewalld creates it itself, and it starts before the daemon). /run/sudo is deliberately not in the unit's ReadWritePaths=: the daemon's sudo children use the NOPASSWD whitelist and never read or write sudo's session directory, so listing it only added a boot-time and restart-time failure mode (sudo removes /run/sudo when the last session ends).

File System Layout

The following file system locations are used for integration with system services:

Path	Purpose	Managed By
/etc/nginx/conf.d/vacuum-wall.conf	Include directive that pulls in data/nginx/sites-enabled/*.conf.	Vacuum Wall (lib/nginx.py)
/etc/nginx/snippets/vacuum-wall-ssl.conf	Shared SSL configuration snippet (protocols, ciphers, DH parameters, OCSP). Included by all HTTPS server blocks.	Vacuum Wall (lib/nginx.py)
/etc/dnsmasq.d/vacuum-wall.conf	Generated dnsmasq configuration file. Written from config/dnsmasq/config.json.	Vacuum Wall (lib/dnsmasq.py)
/etc/wireguard/wg0.conf	Generated WireGuard interface configuration. Written from config/wireguard/config.json.	Vacuum Wall (lib/wireguard.py)
/etc/systemd/network/50-<name>.network	Generated systemd-networkd drop-in files. Written from config/network/config.json, one per interface.	Vacuum Wall (lib/network.py)
/etc/sudoers.d/vacuum-walld	Sudo whitelist for the daemon user. Defines all permitted privilege escalations.	Install script (rendered from Jinja2 template)
/run/vacuum-wall	Runtime directory for secure temp files during config apply (nginx, dnsmasq). Created by systemd RuntimeDirectory=, removed on stop.	Daemon (systemd unit)
/run/nginx	Runtime directory referenced by the daemon's ReadWritePaths=; must exist at spawn. Created by systemd RuntimeDirectory= before namespace setup.	Daemon (systemd unit)
/run/firewalld	Root-owned runtime dir of firewalld. Must exist at spawn because of ProtectSystem=strict + ReadWritePaths= (see volatile-/run note above). Present while firewalld runs; also pre-created at early boot by system/tmpfiles.d/vacuum-wall.conf.	firewalld / systemd-tmpfiles (early boot)
/run/sudo	sudo's session directory. Present only while sudo sessions exist. Not in the unit's ReadWritePaths= (NOPASSWD sudo children never need it) — see volatile-/run note above.	sudo (created/removed on demand)
data/auth.db	SQLite database: users, permissions, token_blacklist, webauthn_creds. Created on first access via get_db().	Auth layer (lib/db.py)

The /etc/nginx/conf.d/vacuum-wall.conf include file ensures that all domain-specific configurations in sites-enabled/ are loaded by nginx without modifying the main nginx.conf. The SSL snippet keeps TLS settings consistent across all managed domains and allows global updates from a single location.

Frontend Architecture

The web UI is a single-page application built on Hoover, a custom lightweight VDOM framework. See Hoover Framework Reference for the complete API.

Request Flow (Frontend)

Client requests / ──→ nginx ──→ Flask (serves index.html)
Client loads /static/app.js ──→ Hoover initializes, checkSession() (401 with valid refresh token → one refresh) → if no valid session, render #login
Authenticated ──→ mounts #sidebar and #main render roots
apiFetch() ──→ injects Authorization: Bearer <token> header ──→ Flask REST API
Flask before_request ──→ validates JWT from header, checks blacklist, verifies permissions
Hoover connects WebSocket ──→ daemon/ws (127.0.0.1:9091?token=<access_token>)
Page navigate (hash change) ──→ reactive router state updates ──→ render engine re-executes ──→ VDOM diff patches DOM
User action (form submit) ──→ apiFetch() ──→ Flask REST API ──→ daemon/client.py ──→ vacuum-walld
Token expiry ──→ refreshScheduler() ──→ POST /api/auth/refresh ──→ new tokens
WebSocket message (versions) ──→ topic match ──→ page load() re-executed ──→ state updated ──→ render engine patches DOM

The SPA entry point only serves index.html at /. All other paths return 404. Non-API, non-static paths are not served by Flask — the client-side router handles all navigation via hash changes. A dedicated /vendor/<path> route serves vendored JS libraries.

Component Model

Each route is a definePage() component with reactive state, async data loading, and WebSocket auto-refresh. Pages are mounted using hComp(page, key) in the router, where the key determines lifecycle boundaries. The same key reuses the component instance (preserving state); a different key unmounts the old page and mounts the new one.

No Build Step

All JavaScript is served as ES modules. Cache invalidation is handled via HTTP cache-control headers. Dev mode (VACUUM_WALL_DEV) disables aggressive static asset caching.

WebSocket Broadcast

The daemon broadcasts state-change notifications via WebSocket. Hoover's subscribe mechanism maps page-level topic subscriptions to automatic load() re-executions. Messages are debounced (300ms) and in-flight loads are aborted before re-loading, ensuring the UI always displays the latest available data.

Zone Model

The firewalld zone layout in Vacuum Wall follows a defense-in-depth approach, segmenting traffic based on trust level:

Zone	Interfaces	Trust Level	Description
public / external	WAN (e.g., eth0)	Untrusted	Internet-facing. Only explicitly allowed inbound services (HTTPS/443, WireGuard/51820, ICMP echo rate-limited) are accessible. All other inbound traffic is dropped.
internal	LAN (e.g., eth1)	Trusted	Local area network. DHCP (UDP 67/68) and DNS (UDP/TCP 53) are served. Masquerade (NAT) is enabled for outbound Internet access from LAN clients. Inbound from WAN to this zone is not directly accessible.
vpn	WireGuard (wg0)	Semi-trusted	WireGuard tunnel interface. Firewall rules determine which internal services and subnets VPN peers can reach. By default, VPN peers can access the Internet but may be restricted from accessing management interfaces or sensitive LAN services.
trusted	Management interface	Administrative	Used for management traffic. The loopback zone covers localhost communication, enabling the Flask WebUI to receive proxied requests from nginx on 127.0.0.1:9090.

Custom Zones

Additional zones can be created for specialized network segments:

• DMZ zone: For hosting public-facing services that need to be isolated from the internal LAN. Traffic from the DMZ to the internal zone is denied by default.
• Guest zone: For visitor Wi-Fi or untrusted devices. Access is limited to outbound Internet traffic only, with no access to internal or vpn zones.
• IoT zone: For devices requiring restricted outbound access (e.g., blocking telemetry domains).

Each custom zone can define its own source rules, port forwardings, and inter-zone traffic policies. The Flask WebUI provides interfaces to create, modify, and assign interfaces to zones at runtime.