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Your Network at a Glance

LanLens gives you a quick, local view of what is on your network:

• Devices found by MAC/IP device discovery, with vendor hints and online/offline state
• A practical device inventory for names, notes, owners, locations, services, ports, and history
• Multi-select cleanup for deleting several unwanted inventory entries in one confirmed action
• Segments for routers, switches, servers, IoT, cameras, clients, and unknown devices, with sortable capacity statistics
• Awareness signals for DHCP, ARP/MAC, LLDP/CDP, STP/RSTP, OSPF, Sophos Security Heartbeat presence, SNMP, custom SNMP OIDs, and scan-detected changes
• Multiple DHCP address ranges for installations scanning several networks, configurable under Settings → Network Discovery
• Export paths for CMDB/i-doit workflows when inventory data should leave LanLens

Why people use it:

• Fast start: a Docker network scanner for networks from home labs to small IT and enterprise environments.
• Less spreadsheet work: turn scan results into a maintained self-hosted network inventory.
• Local by default: no cloud account is required, and there is no product telemetry pipeline.

Optional expert views add SNMP switch-port context with counter-rate trends and MAC-only discovery across learned VLANs, custom SNMP OID/table polling by device class or target tag, a feature-gated network topology map with pan, zoom, draggable device cards, offline-device filtering, relationship/VLAN filters and selected-link evidence details, passive LLDP/CDP/STP/OSPF discovery hints, services, TLS checks, notifications, and CMDB/i-doit integration when you need them. Credentials are masked in API responses; protect the database volume and backups because configured secrets live there.

[!IMPORTANT] Use LanLens only in networks you own or where you have explicit permission to scan and monitor devices. Network discovery and port scanning can be misused against third-party systems.

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Support

LanLens is free and open source. If it helps you or saves you time, you can support ongoing development voluntarily. Support does not buy support priority, features, or access.

Legal notice and project contact information are maintained on lanlens.org/privacy.html.

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Star History

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Product Screenshots

The screenshots below use sanitized demo data with documentation IP ranges and example names.

Dashboard	Device detail

Segments	DHCP security awareness

LLDP/CDP class hints	SNMP targets

SNMP poll diagnostics	Device linked to SNMP identity

Network topology	Network changes

CMDB / i-doit settings	Reviewed i-doit CSV export

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Quick Start

Requirements

• Docker 20.10+
• Docker Compose v2
• Linux host recommended for direct ARP scanning
• A 64-bit x86 (amd64) or ARM (arm64) Linux host

1. Start LanLens

curl -fsSL https://raw.githubusercontent.com/AlexRosbach/LanLens/main/docker-compose.yml -o docker-compose.yml && docker compose up -d

On first startup, LanLens generates a strong SECRET_KEY inside the persistent lanlens_data Docker volume. On a fresh database without a configured scan range, LanLens also detects the primary host IPv4 subnet, stores it as the initial scan range and starts an immediate ARP scan so the dashboard can populate without manual Settings work.

Open:

http://<your-host-ip>:7765

Default first-run credentials:

admin / admin

LanLens forces a password change after the first login. For full MAC/vendor discovery, run it on a Linux host with host networking as shown in the compose file.

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Deployment Notes

LanLens uses network_mode: host by default because local ARP discovery and first-run subnet detection need raw network access on the host interface. Bridge mode can serve the UI, but direct ARP/MAC discovery will not work the same way and may require manually configured scan targets. Additional routed Nmap targets are tracked by IP so hosts such as Docker ipvlan containers remain separate even when they expose a shared MAC address. Routed discovery disables Nmap's implicit ARP ping and ignores spoofed reset replies so proxy ARP or firewall behavior cannot turn a whole subnet into phantom devices.

Core runtime settings:

Variable	Default	Purpose
SECRET_KEY	generated on first start	Encryption/signing key; set manually only when restoring/migrating encrypted credentials
LANLENS_API_TOKEN	empty	Optional persistent Bearer token (minimum 32 characters) for REST integrations
LANLENS_API_TOKEN_READ_ONLY	true	Restrict the persistent API token to GET/HEAD/OPTIONS requests
DEFAULT_ADMIN_PASSWORD	admin	Initial admin password when no user exists
LANLENS_PORT	7765	HTTP port exposed by nginx
BACKEND_PORT	17765	Internal FastAPI port behind nginx
DB_PATH	/data/lanlens.db	SQLite database path
TZ	UTC	Container timezone

For HTTPS, external databases, Scan Nodes, deep scan permissions, CMDB/i-doit, SNMP, backups, and troubleshooting, use the LanLens Wiki.

ARM64

The main LanLens image supports 64-bit ARM hosts such as recent Raspberry Pi models running a 64-bit Linux distribution. Use the same Compose file and image name as on AMD64; Docker selects the matching image platform automatically. Direct ARP discovery still requires Linux host networking plus NET_ADMIN and NET_RAW. A 32-bit ARM userspace is not supported.

Maintainers can validate both supported platforms with docker buildx bake.

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Learn More

• LanLens Wiki: setup, configuration, scanning behavior, integrations, troubleshooting, and common workflows
• DNS names and AXFR: preferred names, alias inventory, read-only zone transfers, optional TSIG, and least-privilege setup
• Changelog: release history and migration notes
• Security Policy: vulnerability reporting and supported versions

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Docker Images

Docker images are published at alexrosbach/lanlens. Use the compose file in this repository for the expected host-network deployment model and required environment variables.

Project updates and occasional build notes are posted on X / @itneedtoknow.

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Development

Backend:

python3 -m venv .venv
source .venv/bin/activate
pip install -r backend/requirements.txt

export SECRET_KEY=dev-secret-key-at-least-32-chars-long
export DB_PATH=./data/lanlens.db
mkdir -p data

python backend/cli/init_db.py
python backend/cli/init_admin.py
uvicorn backend.main:app --reload --port 8000

Frontend:

cd frontend
npm install
npm run dev

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License

MIT License, see LICENSE.

Dependency note: LanLens uses GPL/LGPL and dual-licensed libraries for network discovery and remote connectivity features. See THIRD_PARTY_NOTICES.md before redistributing bundled builds or Docker images.

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OpenAI-Assisted Development

LanLens was developed with OpenAI tools as part of the workflow, including Codex-assisted planning, implementation, debugging, documentation, UI review, and demo preparation. OpenAI support helped accelerate several project highlights:

• Building a clearer device inventory and topology experience from scanner, SNMP, and passive discovery data
• Iterating on the React/FastAPI user experience, including dashboards, device detail views, services, network changes, and expert settings
• Improving documentation, release notes, screenshots, and demo material for the OpenAI Hackathon submission
• Validating changes with focused tests, Playwright checks, and review passes before publishing

GPT-5.6 was also used as one of the OpenAI models during development.