I've been working on a LAN discovery tool with a Terminal User Interface (TUI) written entirely in Go. It's called Whosthere, and it's designed to help you explore devices on your local network without requiring elevated privileges.

It works by combining several discovery methods:

- mDNS and SSDP scanning

- ARP cache reading (after triggering ARP resolution via TCP/UDP sweeps)

- OUI lookups to identify device manufacturers

It also includes:

- A fast, keyboard-driven TUI (powered by tview)

- An optional built-in port scanner

- Daemon mode with a simple HTTP API to fetch devices

- Configurable theming and behavior via a YAML config file

Why I built it:

Mainly to learn, I've been programming in Go for about a year now and wanted to combine learning Go with learning more about networking in one single project. I've always been a big fan of TUI applications like lazygit, k9s, and dive. And then the idea came to build a TUI application that shows devices on your LAN. I am by no means a networking expert, but it was fun to figure out how ARP works, and discovery protocols such as mDNS and SSDP.

Example usage:

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# install via HomeBrew brew tap ramonvermeulen/whosthere brew install whosthere

# or with go install go install github.com/ramonvermeulen/whosthere@latest

# run as TUI whosthere

# run as daemon whosthere daemon --port 8080

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I'd love to hear your feedback, if you have ideas for additional features or improvements that is highly appreciated! Current platform support is Linux and MacOS.

It says 'Open ports: (None)' for all devices on my network, despite there being open ports on many of them (MacOS Tahoe 26.2 / installed via go)

this is great! i had to tweak the config file on macos because it was using some weird interface (utun4) instead of en0. otherwise awesome tool, i am definitely going to be using this more often.

I love the resurgence of TUI apps, but I wonder what the definition of "modern TUI" means in these cases. Does it basically mean just not using curses?

  $ go install github.com/ramonvermeulen/whosthere@latest
  # golang.design/x/clipboard
  clipboard_linux.c:14:10: fatal error: X11/Xlib.h: No such file or directory
    14 | #include <X11/Xlib.h>
       |          ^~~~~~~~~~~~
  compilation terminated.

Overall good work. I'd request an `-i` command-line parameter to specify the interface to scan (and I'd prefer ALL params being able to be read from command line params). I think it just performs a full scan initially on my laptop, following scans either didn't success or didn't involve TCP connect scan (I don't see ARP requests after the initial scan).