Let's say I’m using a Dell Inspiron Laptop. Does my ISP have a log of this or can they detect what devices are connected to my router?


4 Answers 4


The Possibilities

If you are using a modem and router provided by your ISP, then they can potentially have full access to data about your connected devices. This is because if you are using their device, then you don't really have a network of your own - your house is just an extension of their network. Some ISPs may use off-the-shelf hardware, in which case they may not take advantage of their access to your home. However, since they provided the hardware, they also have an opportunity to customize the firmware (the software running on the router) to do whatever they want. The router certainly knows about all the devices connected to it, and it would be very easy for them to customize the device to send them data about what devices are connected and when. It wouldn't surprise me if many companies do this for general data collection purposes or to look for violations of their terms of service. In many jurisdictions (especially the US), I'm sure doing so would be completely legal. Whether or not any particular ISP is actually doing this is another question, and difficult for us to answer.

Regardless of whether or not An ISP tracks your devices through your router, they can still see all of your network traffic of course. This means they can read any traffic that goes across in plain text (which primarily, but not exclusively, means HTTP). If you use their DNS servers (which will be the case unless you change it yourself) then they can also tell what sites you visit, even if over HTTPS. Lots of information about your devices can be gathered from your traffic, so they probably wouldn't have any trouble tracking connected devices exclusively through your HTTP traffic, as long as the devices are actively fetching data from the internet.

Actionable Steps

If you are concerned about the possibility, then the simplest solution is to use your own modem or router. Some ISPs effectively require use of their modem (for instance, I'm still using the modem provided by my ISP because it is difficult to find modems compatible with their network). Fortunately, using a different router is the important part. If you plug your own router into their modem and connect your devices only to your router, then you will make it much harder for your ISP to keep track of which devices are connected. After all, the only device they will directly "see" is your router.

Once you are using your own modem you can configure it to use a public DNS service (opendns or cloudflare for example). There is a lot of information hiding in your DNS queries, so this is an important step for the privacy-conscious.

If you really want to hide info from them though you'll mainly want to setup a VPN service 24/7. They must be properly configured to make sure you don't leak data though, so it helps to know what you're doing when setting one up. Personally I don't think that step would be worth it for the average user, but that's a decision for each person to make on their own, especially given recent news coverage about regulatory changes (at least in the US) that may give ISPs more rights to sell the data they collect about you.


  • It’s a netgear router with trash firmware...so I’m good,right? Lmao when I log into my router through my public IP or whatever, it shows only the MAC address.
    – NRSJ
    Commented Feb 7, 2019 at 15:15
  • @NRSJ lol! Some of the netgears actually have great support for open firmware. It certainly varies by model number. Of course I wouldn't go installing new firmware on their modem, but that makes it hard to guess. They might be using generic netgears because they are cheap and easy to work with, and so they don't have to make modifications. Or they may be using them because they are easy to modify. Commented Feb 7, 2019 at 15:22
  • I have a netgear r6300...pretty generic
    – NRSJ
    Commented Feb 7, 2019 at 15:24
  • @NRSJ I'm sounding mildly paranoid here but I don't actually worry too much about ISP tracking my internet usage anyway. Personally, I try to approach the internet from the perspective of "Everything I do and say will be discoverable by someone who cares enough anyway", so I just assume I have no privacy (hence my actual name on my profile). That may not work for everyone, but unless you are doing things illegally, ISPs tracking your internet probably won't have much practical downsides for you. It's just kind of the cost of doing business. Commented Feb 7, 2019 at 15:24
  • I’m just curious on how data is collected by ISP’s and the privacy
    – NRSJ
    Commented Feb 7, 2019 at 15:27

Yes they do,

Actually in some places they are even required by law to identify and maintain a continuous record of all your hardware MACs and access times for criminal prosecution.
Actually there are multiple protocols designed for this purpose, like TR-069. https://en.wikipedia.org/wiki/TR-069


Yes your ISP can detect partially what devices you have plugged on your network. Here is a small list of basic techniques that they can use are:

  • Check the User-Agent field of your HTTP traffic, the easiest.
  • Check some of the TCP/IP fields in order to detect the operating system.

The effectiveness of them depends on the device and how secure have the communications with the outside world.

  • Do they log what devices are connected to your network? Lets say i no longer have the device? Can they go somewhere and determine that at this point of time, he had this device. Kind of like an IP log assignment
    – NRSJ
    Commented Feb 7, 2019 at 14:30
  • Probably your ISP logs a lot of information, regarding of the devices connected, ask them
    – camp0
    Commented Feb 7, 2019 at 15:21
  • @camp0 I would be interested how you would detect the OS through TCP/IP packets
    – user163495
    Commented Sep 2, 2019 at 14:56
  • 1
    Check the tool p0f is great for OS detection at TCP/IP level (lcamtuf.coredump.cx/p0f3)
    – camp0
    Commented Sep 2, 2019 at 14:58

If you are truely paranoid, then yes, your ISP can detect and log any device connected to their router. They have full control over the router software, so they can install a spyware to upload them everything that the router could detect. At the simplest level, MAC address, and with little effort, the OS of the device, at a higher level, every shared disk or printer, and the router could even provide access to any shared disk.

Can reasonably such a spyware be installed by the ISP? Only my opinion, but I would think the risk very low and acceptable - but I have no atomic code on my devices...

It is as usual a matter of threat and acceptable risk level. If the most confidential data that is present on your devices are the messages you exchange with your lover(s), and the codes for your banking service, I would trust the ISP (after all, you chosed them, and confidential data should have an additional protection level). If you are hosting some top secret mission critical data, things are really different, and you should not trust the ISP provided router, and instead install a fully controled firewall between it and your internal private network.

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