Free network monitoring for your own network, with every feature

What you get

• Every feature

  Nothing is switched off: discovery, detection, the asset inventory, industrial protocol decoding, notifications, the API and optional response. Detection keeps working on every device even above the limit.

• Yours, on your hardware

  Linux on x86-64 or ARM64 (including a 64-bit Raspberry Pi), macOS or Docker. No account, no DENIS cloud, no telemetry. The data is one local database file.

• Signed and kept up to date

  Signed, pre-built releases, a signed installer, and security updates of your version line that install by themselves unless you switch that off.

For a home network or a home lab

A device list that keeps itself current, a map of who talks to whom, and an alert when a camera suddenly calls an address it never used, a visitor’s phone joins, or a gadget goes quiet. Every alert says why it matters and what to do first.

• No spreadsheet to maintain: devices appear as they join, and new ones wait in a review queue.
• Alerts in the console and, if you like, in e-mail, ntfy, Slack, Discord or a webhook.
• If your switch answers SNMP, DENIS also draws the switches and the cables between them.
• A sandbox for learning: industrial protocols, detection rules you can write yourself, packet captures you can replay with denis replay.

DENIS · Notifications

Start in two steps

$ mv denis-* denis && chmod +x denis
$ ./denis demo --db demo.db load && ./denis serve --db demo.db --insecure-no-auth

$ curl -fLO https://github.com/stefanmesaros/denis/releases/latest/download/install.sh
$ less install.sh      # it runs as root: read it first
$ sudo bash install.sh

Guides

• Install on a small Linux machine
• SPAN port and TAP placement
• Switch visibility over SNMP
• Quick start (documentation)

Take part

DENIS is developed in the European Union (Slovakia), and reports from its users decide a lot of what is fixed and verified next. Verifying hardware takes a long time and nobody owns every device, so a report from your switch, firewall or controller, including “it did not work”, is especially useful.

• DiscordAsk questions, compare notes and share what you find.
• GitHub issuesReport a problem or suggest an improvement.
• Tester guideWhat to try first and how to report it usefully.
• RoadmapWhat is planned, without dates.

The source code is maintained privately, so code pull requests are not possible. Reports, documentation feedback and hardware results are welcome.

The license in plain words

• DENIS Community is free for personal, non-commercial use on a single installation monitoring up to 100 devices, under the DENIS Community License. It is distributed as signed, pre-built binaries.
• Above 100 devices nothing is switched off: detection and alerting keep working on every device, and the Devices page shows the first 100.
• Trying it at work: An organisation may use the Community edition free of charge for 30 days from its first installation, on up to 100 devices, to evaluate and demonstrate DENIS (not to run its operations). After that it stops using DENIS or gets a commercial license. Installing again does not restart the period, and DENIS does not count the days or switch itself off: the condition is in the license. See information for organisations.
• Any other use by or for a business, non-profit, government body or other organisation needs a separate commercial license, whatever the number of devices.
• You may not redistribute DENIS. The license has the exact terms.