Recommendation for learning about network traffic

I want to be able to look at and understand the network traffic coming in and out of my house. I know enough to use Activity Monitor and things like iStats for one computer, but I’m really more interested in understanding/viewing it from the modem level – I have lots of variation in my download/upload speeds with no discernible cause, and 6 devices that could be contributing to the issue.

Can anyone recommend good beginner guides for understanding/tracking network data?

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You’ll need a good way to instrument the traffic.

Any Linux system/box can be rigged to do it. For consumer, devices like the Firewalla can be a good way to dip a toe into the water.

Full blown analysis, you’ll want to learn Wireshark and have a good NIC. TBH, if something requires dusting off my WireShark skills, I’m strongly motivated to find another, any other, way to solve the problem instead :laughing:

TL;DR - You’ll want an in-line device attached to your WAN connection so you can see the actual traffic in and out. Looking from a client device like your Mac doesn’t have the visibility to see everything before processing or fitering has been applied.

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Running the Little Snitch app and all the background info available at the maker’s ObjDev website might also be a good start.

Objective Development


Thank you both. Some good starting points and things to consider.

I know somebody that an issue with their upload/download speeds from their cable modem. Turns out that the line from the provider was chewed up by squirrels. Test each step of your connection - line into your house, cable modem, ethernet cables, and wifi router. Try to narrow down which component is causing the variability. I start by testing everything wired to reduce the variability.


After some internet speeds improvements last year I started to try to learn more about networking. YouTube has a few videos that go over everything in a big picture type way, but often going down to the small home network level wasn’t very helpful. Watching them made me want to set up my own home lab with a Unifi network though. :slight_smile: One channel I found helpful is called Crosstalk Solutions, but there is a ton of stuff out there.

One thing I had overlooked for 2 years is that my internet plan was faster than my router supported. My old Eero only had a 1 GbE port. My plan was 1.2 Gbps. So I could never get full speed from a wired connection. Finding routers with faster ports isn’t difficult, but the prices go up quite a bit when you get into that area, especially if you want more than one 2.5-10 GbE port.

So now I am on fiber, and wired connections are blazing fast, but almost nothing I own supports Wifi 6e, so everything is still slow…