See who's on your Wi-Fi: name, model, maker, IP, first seen — and why a device can't be identified.
Open System Settings → Privacy & Security → Local Network and turn on the switch beside Census. (The button on that screen in the app takes you straight there.) Census picks it up on its own within half a minute — or click I turned it on — try again and it starts right away. You never have to restart the app.
Without that permission the list stays empty, which is not the same as your network being empty. Census says which of the two it is.
Phones, tablets and many laptops make up a random hardware address for every network they join, so there is no maker to look up. It's a privacy feature working as intended, not a fault in the device or in Census.
To confirm it yourself on an iPhone or iPad: Settings → Wi-Fi → ⓘ beside the network → Private Wi-Fi Address. Turn it off and the device shows its real maker in Census the next round.
Guest networks, hotel Wi-Fi and many mesh systems turn on client isolation, which stops devices on the network from seeing each other at all. No app can look past that. Switch to your main network instead of the guest one, or look for "client isolation" or "AP isolation" in your router's settings.
Nothing is ever dropped — the line at the top always tells you what you're looking at. The picture changes with the size of the network:
The list view has a search box (⌘F) that matches names, addresses, makers and models, and shows how many of the total matched.
It asks each address in your own subnet whether anything is there, listens for the service announcements devices already broadcast, and — if you leave that switch on — opens a short connection to eighteen common ports per device to see what each one offers. Nothing is changed on your network or on the devices; Census only looks, and only from this Mac.
A quiet re-check runs every 30 seconds by default. You can make it slower, or turn off the port check entirely, in Settings. On networks with more than eighty devices Census skips the port check by itself and tells you it did.
Give any device your own name and it's used everywhere, with the device's own name kept underneath. Mark a device as known and it stops being reported as new and stops sending notifications. Both, and the record of what has been seen, stay on this Mac; Settings → History → Forget everything erases them.
File → Export as CSV or JSON writes the devices currently listed, with the columns you see. CSV timestamps are in your Mac's local time so spreadsheets read them as dates; JSON keeps UTC for machines.
Check System Settings → Notifications → Census is allowed — if macOS is holding them back, Census says so in its own Settings window. Only devices this Mac has never seen trigger one, and marking a device as known stops it.
Email lsc7@foxmail.com with your macOS version and what you saw on screen. Purchases and refunds are handled by Apple through the App Store.
一屏看清谁在你的 Wi-Fi 上：名字、型号、厂商、IP、第一次出现的时间，以及认不出的时候是为什么。
打开系统设置 → 隐私与安全性 → 本地网络，把 Census 右边的开关打开（引导页上的按钮会直接带你过去）。半分钟内它会自己再查一轮；也可以点引导页上的「我已经打开了，再试一次」立刻重来。不用重开应用。
没有这个权限，列表就是空的——但那和「你的网络上没有设备」是两回事，网内点名会告诉你是哪一种。
手机、平板和不少笔记本每加入一个网络就编一个随机硬件地址，所以查不到是谁做的。这是隐私功能在正常工作，不是设备有问题，也不是网内点名出错。
想自己确认：在 iPhone 或 iPad 上打开设置 → 无线局域网 → 这个网络右边的 ⓘ → 私有 Wi-Fi 地址，关掉它，下一轮这里就会显示真正的厂商。
访客网络、酒店 Wi-Fi 和很多 Mesh 系统会打开「客户端隔离」，让网络上的设备完全看不到彼此，没有任何应用能越过这一层。换回你的主网络别用访客网络，或者在路由器设置里找「客户端隔离 / AP 隔离」。
一台都不会被丢掉——顶上那行字随时告诉你现在看到的是什么。图会随网络的大小换一种画法：
列表那一侧有搜索框（⌘F），名字、IP、厂商、型号都能搜，右边写着一共匹配到几台。
它向你自己网段里的地址逐个问一声「在不在」，听设备本来就在广播的服务信息，并且——如果那个开关开着——对每台设备的十八个常用端口各开一个很短的连接，看它提供什么。你的网络和上面的设备都不会被改动；网内点名只是看，而且只从这台 Mac 看。
默认每 30 秒静默复查一轮。可以在设置里调慢，也可以把端口检查整个关掉。设备超过八十台时它会自己跳过端口检查，并且把这件事说出来。
你可以给任何设备起自己的名字，列表和图上都会改用它，设备自己的名字仍在下面显示。标为「认识的」之后，它不再算作新设备，也不再为它发通知。这些和「见过哪些设备」的记录都只存在这台 Mac 上，设置 → 历史 → 忘记全部历史可以全部清掉。
「导出 CSV / JSON」会把当前列出的设备连同你看到的那些列一起写出来。CSV 里的时间用本机时区，表格软件会认成日期；JSON 保留 UTC，那是给机器读的。
检查系统设置 → 通知 → Census 是否允许——如果被 macOS 拦住了，网内点名会在自己的设置窗里说出来。只有这台 Mac 从没见过的设备才会触发通知，标为「认识的」之后就不再通知。
写信到 lsc7@foxmail.com，附上 macOS 版本和屏幕上看到的内容。购买和退款由苹果通过 App Store 处理。