monitor modem traffic

Internet stuff is an area where my depth is really pretty shallow.

I need a program that will monitor live, traffic sent and rec’d by my cable modem. I contacted the ISP but they say they have no way to monitor traffic but the reset my modem. Which my OR MAY NOT help.

The problem is my daily usage went from an average of 10 to 30 gbs to 65 to 95. and my actual usage hasn’t changed much - depends on how many on-line conferences I attend and how much we stream Netflix (which has increased with covid).

Have monitored Network tab of ActivityMonitor but nothings really looks odd.

I’m on a Mac Pro with Mojave.

thanks if anyone can point me toward a monitor program. I think I have a bad modem but have to convince the cable company.

Does your cable modem just have a wired ethernet cable that feeds a separate router and wifi access point? Or does the cable modem itself also act as a router and access point? If you don’t know what you have, give us the brand and model of the modem.

If the modem also is the router and access point, it becomes much harder to monitor all the traffic. It then depends on what that modem supports in terms of diagnostics, monitors, or bandwidth tracking.

If the modem just feeds another router and wifi access point(s), then that becomes the best source to monitor the traffic. Some models provide their own bandwidth tracking per device, especially if they also offer device tracking or parental controls.

I’m assuming here you have multiple devices that use the internet in addition to your Mac Pro, such as smartphones, smart TVs, guests, etc.

I do this for the modems at my mom’s and my mother in laws place. The modems have a webpage that gives all that information and I have a little program that just queries it and regularly updates the information. In my case it goes into the automation software I write for a living :wink: which is here if you have any interest :wink:

If the modem has a page that has this information you can regularly ask for it and then do whatever you want with the info. If the info comes already inside the page then parsing it out can be a challenge. If the page makes an xhttp request in order to display it then it will be hugely easier. You just need to duplicate that and parse the JSON or XML response! The Web Inspector on Safari or the developer tools in any of the other major browsers are your friend here to help you figure out how to find it and how the built in interface is getting it.

The downside is if the modem itself doesn’t have an interface to this information, or if the user has it setup in bridge mode to allow some other device to do the work of managing the NAT and sharing and what have you. In that case you need to connect to the device that is actually the router and not the bridge and see if it has the interface needed to get that information.

the other thing you might find is an snmp client that can talk to that specific modem