Scanning

Tools that find things on a network — open ports on a host, services advertised via mDNS/Bonjour, live devices across a subnet, and long-running reachability of a watchlist.

Port scanner

A TCP-connect scanner with a curated list of well-known service names. Works against a single host at a time, streams open ports as it finds them.

• Host — hostname or IP (IPv4/IPv6).
• Range — choose one of:
  • All — ports 1–65535.
  • Well-known — 1–1023 (system / IANA registered).
  • Dynamic — 1024–65535 (ephemeral / user).
  • Range — custom from–to.
  • Single — one port.
• Results — open ports with their service label from the bundled serviceports.csv (e.g. 22 — ssh, 443 — https, 5432 — postgresql).
• Stop anytime — the button flips to Stop while the sweep runs.

Scanning someone else's network is usually illegal without permission. The banner shown on first use makes this explicit. The scanner uses TCP connect, which is visible to any IDS worth its salt.

Reading the results

• Open port — the three-way handshake completed. The service underneath may still reject the session at a higher layer (authentication, TLS SNI).
• No results — all ports either closed or filtered. The tool does not distinguish the two; a stateful firewall silently dropping packets looks the same as "nothing listening".
• Partial results on large ranges — full 1–65535 sweeps take a while on mobile radios. Narrow the range when you can.

Bonjour / mDNS discovery

Listens for multicast DNS announcements on the local segment. Shows every device advertising at least one service and the full list of what each is offering.

• No input — the scan runs for 30 seconds after opening the screen, with a refresh button to restart.
• Results — grouped by hostname. Each row expands to show all service types (e.g. _http._tcp, _ssh._tcp, _ipp._tcp, _airplay._tcp, _smb._tcp), with ports and TXT records.
• IP addresses — both IPv4 and IPv6 link-local (fe80::) are exposed; each is long-press-copyable.

iOS requires Local Network permission (system dialog on first run). Android needs Wi-Fi enabled and location permission (see Settings & platforms for why). Cellular-only devices can't do mDNS — the screen shows a hint.

Network map

A visual ping sweep of the local subnet. Picks the active network interface (or you choose from a list when there's more than one), assumes a /24, pings every host and lays responders out on a ring around the default gateway.

• Gateway — resolved from the system's routing table. Shown as the central node.
• Found hosts — placed on an inner ring (first 8) and outer ring (the rest). Tap a node for details.
• Concurrent pings — the global Concurrent pings value (default 10, range 1–50) bounds parallel probes so the radio doesn't get overwhelmed.

The scan ends when all 254 addresses have been tried. Tap Stop to cancel early.

Hosts in range

The text-mode counterpart to Network map. Same sweep, same timeouts, but presented as a sortable, searchable list with more data per host.

• Interface picker — one row per active interface (e.g. wlan0 - 192.168.1.42).
• Mask — /16 through /31, default /24. Wider masks trade scan time for coverage.
• Per-host columns — IP, hostname (forward+reverse DNS), mDNS name, ping stats (tx/rx, loss%, min/avg/max/mdev RTT).
• Filter — a search box narrows by substring. Toggle between All, Connected, Other.

Host monitor

A persistent watchlist of hosts you care about, organised into groups. Each host remembers its last state and timestamp; tap Ping all to refresh everything, or Ping group / Ping host to refresh a smaller scope.

• Groups — arbitrary, renameable, deletable. Collapse a group to hide its hosts.
• Hosts — hostname or IP, per-group. Long-press opens actions (jump into Ping, Traceroute, etc.).
• Status chip — green Reachable, red Unreachable, yellow Cancelled, grey Unknown. Timestamp underneath shows when the state was last observed.
• Cancel — the button swaps to Cancel while pinging; incomplete hosts keep their previous state.

Free tier caps the total number of saved hosts across all groups. PRO unlocks unlimited. The dialog shows up automatically when you hit the ceiling.

Common patterns

• Group per location — Office gateway + office servers, Home NAS + router. A single tap verifies a whole site.
• Group per customer — keeps client data separate when you spin through sites.
• Probes for alerts — put known-good public servers in a Canary group to tell "my internet is down" from "the customer's site is down".