At home I have a fairly extensive network setup that includes numerous switches, wired connections in most rooms, Wi-Fi and over 100 connected devices. Amongst those 100+ devices are numerous Alexas, Raspberry Pis and smart devices in addition to the computers, laptops, tablets, phones, watches and all the usual things.
Introduction ngrok and similar tools are great for providing public access to local services, often for development purposes. I primarily use it for exposing an API being developed locally so that a webhook callback can interact with it, for example an inbound email callback from mailgun - it's very useful
Recently when installing MySQL workbench on a clean Ubuntu 20.04 install I've run into the following error when connecting locally using a stored password: "An AppArmor policy prevents this sender from sending this message to this recipient.." This post on MySQL forum suggests its a permissions issue between MySQL
Serial console Note: This note was originally in the Raspberry Pi, overlayfs read-write root, read-only NFS base post. It's quite easy to listen on the serial console as you don't have to worry about the voltage differences. Full documentation here. I have many Prolific Technology, Inc. PL2303 Serial Port devices
Watching the file-system Note: This note was originally in the Raspberry Pi, overlayfs read-write root, read-only NFS base post. NFS logging appeared to be quite opaque to me, so it proved useful to be able to observe the relevant file-system activity. We can watch the file-system activity (when the Pi