A native macOS network scanner and security auditor — built entirely in SwiftUI.
NetGuard scans your local network, identifies every connected device, checks open ports, inspects SSL certificates, detects known vulnerabilities, and runs a passive security audit — all without sending any data outside your machine.
No telemetry. No cloud. No subscription.
⬇ Download the latest release (.dmg) — signed with a Developer ID and notarized by Apple, so it runs without Gatekeeper warnings.
Open the .dmg, drag NetGuard to your Applications folder, and launch it. Grant Local Network access when macOS asks. Requires macOS 15.0+ on Apple Silicon.
Prefer to build from source? See Build & Run below.
| Network Map | Device Detail |
|---|---|
 |
 |
| Alerts Panel | Filter by Device Type |
|---|---|
 |
 |
- Full scan — ping sweep → port scan → OS fingerprinting → service enrichment
- Quick scan — host discovery only (no port scan)
- Resolves hostnames via DNS, mDNS/Bonjour, and NetBIOS
- OUI vendor lookup from MAC address
- OS guessing from TTL fingerprint
- Interactive topology view — router at center, devices in orbit
- Zoom in/out with scroll wheel, trackpad pinch, or ± buttons
- Filter by device type (router, computer, phone, IoT, printer…)
- Search bar for quick device lookup
- Click any node to open the detail panel
- Risk score (0–100) per device with color-coded gauge
- Detects dangerous open ports: Telnet, FTP, VNC, RDP, SMB, exposed databases…
- Checks for expired or self-signed SSL certificates
- Tests default credentials (admin/admin, admin/1234…) against web interfaces on LAN
- Flags unknown devices as potential intrusions
- Compares each scan against the known-device database
- Sends a macOS notification when a new device appears on the network
- Persistent alerts panel with severity levels: critical / high / medium / low
- Every scan is saved as a
ScanSnapshot(SwiftData) - History tab shows date, duration, device count, alert count, new device count
- Delete individual entries via context menu
- IP, MAC, vendor, hostname, open ports
- HTTP banner and page title
- SSL certificate details (subject, issuer, validity, trust status)
- Security audit results with per-finding explanations
- "Open in browser" button (shown only when a real HTTP interface is detected)
- "Diagnose network" shortcut → opens macOS Network Preferences
NetGuard/
├── NetGuardApp.swift
├── ContentView.swift ← HSplitView (Sidebar | Map | Detail)
├── Models/
│ ├── NetworkDevice.swift ← core entity
│ ├── NetworkAlert.swift ← security alerts
│ ├── ScanResult.swift
│ ├── ScanSnapshot.swift ← SwiftData scan history
│ └── CertificateInfo.swift ← SSL certificate model
├── Services/
│ ├── AppState.swift ← @MainActor central ViewModel
│ ├── NetworkScanner.swift ← ping sweep via /sbin/ping
│ ├── PortScanner.swift ← NWConnection port scan
│ ├── DeviceEnricher.swift ← mDNS, NetBIOS, HTTP, SSL
│ ├── SecurityAuditor.swift ← actor — risk score + credential check
│ ├── VulnerabilityChecker.swift ← generates NetworkAlert list
│ ├── NotificationService.swift ← UNUserNotificationCenter
│ ├── NetworkMonitor.swift ← NWPathMonitor
│ ├── NetworkInfoService.swift ← local IP, gateway, Wi-Fi info
│ ├── OUIDatabase.swift ← MAC → vendor lookup
│ ├── SSDPDiscovery.swift ← UPnP/SSDP discovery
│ ├── CertificateInspector.swift ← SecTrust / SecCertificate
│ └── ScanCache.swift
├── Views/
│ ├── SidebarView.swift ← metrics, alerts, scan controls
│ ├── NetworkMapView.swift ← interactive topology map
│ ├── DeviceDetailView.swift ← right panel — full device info
│ └── HistoryView.swift ← scan history tab
└── Utils/
├── L10n.swift ← type-safe localization enum
└── Localizable.xcstrings ← FR + EN string catalog
Concurrency model
- All services are
actor-isolated (Swift 6 strict concurrency) AppStateis@MainActor— single source of truth for the UISecurityAuditorruns credential checks on a background actor, never on main thread
| Requirement | Version |
|---|---|
| macOS | 15.0 or later |
| Xcode | 16.0 or later |
| Swift | 6.0 |
| Architecture | Apple Silicon (M-series) |
NetGuard is not sandboxed — it requires direct network access (
/sbin/ping,NWConnection,nmblookup). Distribution outside the Mac App Store only.
git clone https://github.com/Lyosis/NetGuard.git
cd NetGuard
open NetGuard.xcodeprojSelect the NetGuard scheme, choose My Mac, then press ⌘R.
No external dependencies — no SPM packages, no CocoaPods.
Note: the first scan will prompt for Local Network access. Grant it when macOS asks.
NetGuard requires the following on first launch:
| Permission | Reason |
|---|---|
| Local Network | Discover and scan devices on your LAN |
| Notifications | Alert you when a new device is detected |
No other entitlements are requested. NetGuard never connects to the internet.
The UI is fully localized in English and French. NetGuard follows your macOS system language automatically — no in-app setting required. On a system set to any other language, it falls back to English.
To add another language, open NetGuard/Localizable.xcstrings in Xcode, add the language, and translate the strings. Contributions welcome.
- English localization (EN + FR, follows system language)
-
NWBrowser— replacedns-sdsubprocess for Bonjour discovery -
SFCertificatePanel— native macOS "View Certificate" button - Advanced device fingerprinting (Bonjour services × HTTP banner × OUI)
- User notes per device (persisted in SwiftData)
- VoiceOver / Accessibility labels
- FoundationModels — on-device AI security recommendations (macOS 26 + Apple Intelligence)
Pull requests are welcome. For significant changes, please open an issue first to discuss what you'd like to change.
Feature branches → PR → merge to main
Code style: follow Swift API Design Guidelines, Swift 6 strict concurrency, no force-unwraps in production paths.
MIT © Wilfrid Bombilaj
Built on Apple Silicon · SwiftUI · Swift 6 · No telemetry