mdns-cli

name	mdns-cli
description	Use when discovering, listing, or inspecting mDNS / DNS-SD ("Bonjour"/Zeroconf) devices on the local network with this repo's `mdns` CLI — e.g. "what's advertising on my network", "find the AirPlay/Chromecast/printer devices", "scan for a service type", "watch the network", or scripting device discovery into JSON/NDJSON.

mdns CLI

A command-line mDNS / DNS-SD device-discovery tool. Lives in src/mDNSDiscovery (project mDNSDiscovery.Cli, assembly/command mdns) and shares its discovery engine with the Blazor web app via mDNSDiscovery.Core.

Running it

From the repo, no install needed:

dotnet run --project src/mDNSDiscovery -- <command> [options]

Everything after -- goes to the CLI. As an installed .NET tool the same commands are just mdns <command> [options] (see "Install as a tool" below).

Commands

Command	What it does
scan	Discover devices once, print, then exit.
watch	Keep scanning and refresh the view until Ctrl+C.
list-types	Print the catalog of mDNS service types that get scanned.

Run ... -- <command> --help for the authoritative option list.

Options

Option	Alias	Commands	Default	Meaning
--service	-s	scan, watch	(full catalog)	Service type to scan for; repeatable. Shorthand (airplay) or full type (_airplay._tcp.local.). Omit to scan the whole catalog.
--timeout	-t	scan, watch	scan 5, watch 2	Seconds to listen for responses in each scan window.
--interval	-i	watch	30	Seconds to wait between scan cycles.
--format	-f	all	table	table, json, or ndjson.

All service types are resolved within a single scan window, so --timeout is the total listen time, not per-type.

Output formats

• table — human-readable Spectre.Console table (Name · IP · Services · Port). watch renders this as a live-updating table.
• json — one pretty-printed JSON array of device objects (full TXT records included).
• ndjson — one compact JSON device object per line; stream-friendly. In watch, any non-table format streams NDJSON, re-emitting the current device set each cycle.

Exit codes (scan)

• 0 — at least one device found.
• 2 — no devices found (lets scripts branch on "nothing there").
• 130 — interrupted with Ctrl+C.

Examples

# One-shot scan of the whole catalog, pretty table
dotnet run --project src/mDNSDiscovery -- scan

# Only AirPlay + Chromecast, 8-second window
dotnet run --project src/mDNSDiscovery -- scan -s airplay -s googlecast -t 8

# Machine-readable, piped into jq (suppress build noise with -v q or 2>/dev/null)
dotnet run --project src/mDNSDiscovery -- scan -f json 2>/dev/null | jq '.[].name'

# Stream NDJSON of printers as they appear, one device per line
dotnet run --project src/mDNSDiscovery -- watch -s printer -s ipp -f ndjson

# Live dashboard of everything, rescanning every 10s
dotnet run --project src/mDNSDiscovery -- watch -i 10

# What service types does it know about?
dotnet run --project src/mDNSDiscovery -- list-types

Install as a tool

The project is packaged as a .NET tool (ToolCommandName=mdns):

dotnet pack -c Release src/mDNSDiscovery -o ./nupkg
dotnet tool install --global --add-source ./nupkg mDNSDiscovery.Cli
mdns scan            # then invoke directly

Use --tool-path <dir> instead of --global for an isolated install, and dotnet tool uninstall --global mDNSDiscovery.Cli to remove it.

Notes

• Needs a real local network; results depend on what's advertising via mDNS at scan time.
• To change the set of scanned service types, edit ServiceCatalog.Default in src/mDNSDiscovery.Core/ServiceCatalog.cs — the CLI and the web app both use it.
• The CLI reports raw TXT-record properties. Friendly per-vendor parsing (AirPlay/HomeKit/etc.) lives in the web app, not the CLI.