rvermeulen98

Just released version v0.2.1 eliminating the need for CGO, thanks for your contribution!

The goal has never been to create something that can replace nmap, the goal was to learn more about networking and about building TUIs in Go. Honestly I am quite overwhelmed by the amount of traction it got today, definitely not what I expected.

I am very grateful for all the feedback and suggestions, and I will take my time to evaluate every comment. In the coming weeks I will try to implement most of the feedback and do releases to improve the tool further, thanks everyone!

In the current version yes, never intended to build it as pure cli app. But if there is a lot of interest in this functionality this is something I can focus on in upcoming releases.

I started off using tview/tcell, and only later found out about bubbletea and the charmbracelet ecosystem. Then I didn't really find a solid reason to switch over to bubbletea. So far I really enjoyed the experience building the app with tview, the only real limitation I ran into was switching the theme at runtime, for which I had to build a custom mechanism.

Would it help to get it on the "official" homebrew, instead of a custom tap/cask? Might try to do an application for that somewhere in the upcoming weeks.

Thanks a lot for your contribution, this is something I will look into in the upcoming days. I totally agree that CGO isn't ideal, I had to make the build/release process also a lot more complicated purely for that clipboard requirement (see GHAs and the different goreleaser files).

On the other hand, I also don't want whosthere to be depended on a fork that isn't maintained anymore. I will think about this trade-off, but I am also interested how others look at this problem.

Thanks for sharing! This is definitely something I will look into, I am all in favor to simplify the current implementation of finding the "default" OS network interface.

Thanks, I am glad you like it! I couldn't find a Go API that just returns the OS "default" network interface, so struggled a bit with a correct implementation for that part.

When reading some blog posts, I found often a solution where it sends out an UDP dial to for example 8.8.8.8:53 because you can then get the network interface back from the connection it's local address. As fallback I implemented to pick the first non-loopback interface that is up.

Would be open to suggestions to do this in a better way!

It doesn't start port scanning by default, maybe this is a feature I can build in the future. When you are on the `detail` view of a device, you can press `p` and that will open a pop-up to perform the port scan. Also the list of ports that will be scanned is a default list of common ports, and can be configured via the configuration yaml.

That's correct. To avoid overloading the local network, the initial scan has a built-in safeguard:

1. It only scans the subnet of the configured network interface.

2. The scan is limited to a maximum size of a /16 subnet.

3. It runs just once every 5 minutes (this interval should be made configurable, currently still hardcoded).

If a subnet larger than /16 is configured, whosthere will log a warning and only scan the first /16 portion of that subnet. As of now the network interface itself is configured via the YAML file. I agree it would be a good idea to add command-line flags for more of these settings to make them easier to adjust.

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:

---

# 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

---

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.