Can ISP know which network a person is logged in via?

If for example I am in a building containing 150 offices. They are all serviced by the same ISP. Each floor has a router servicing 30 offices each.
I log on through Thompson Construction wifi network using their password. I know the ISP can see my IP address is logged on to their system but can they know I am logged on through through Thompson Construction or do they just know I am logged on via a specific router/access point?
Thanks

The ISP? Basically no.

To 'them' you are just a connection originating frrm the external/WAN address of the router/gateway device attached to the ISP. They cannot 'see' beyond that, i.e. how you are connected internally past that, whether further routers, switches, access points etc.

It's more likely that sites and places you visit, the device/OS and browser combination you are connecting with will be able to convey some more useful information. This is known as tracking and fingerprinting.

The "internal" network(s) - completely different ballgame. Yes they can know much more.

Please explain what you ,mean by internal network?

It sounds to me like the ISP's customer is Thompson Construction, who are providing a service throughout the building.

Possibly serviced offices? That sort of thing.

Who do you pay for your broadband?

Yes I am talking about serviced offices in the example I gave. Thompson is just a fictional example of a small office, one of many serviced by the same ISP.
We could call the ISP Amino Services for example. Now lets say I am logged in via Thompsons office connection which is Thompson wifi. Will the ISP know In am logged in specifically via Thompsons and SSID.
Or would it just be able to see that someone is logged in via a particular router/access point in the building without knowing via Thompsons wifi?
Also is it possible for different offices in the same building to have the same IP address?
I hope that is clear, thanks

In reply to a post by DaveySmith55fp:

Or would it just be able to see that someone is logged in via a particular router/access point in the building without knowing via Thompsons wifi?

They don't know how you are connected (unless you're connected directly to the WAN), it just looks like another connection to them. They don't know if you're connected over Ethernet, Wi-Fi, satellite, or even a carrier pidgeon. All they know is you're connected to something that's connected to a router that's connected to them.

In reply to a post by DaveySmith55fp:

Also is it possible for different offices in the same building to have the same IP address?

Yes, if the router is doing NAT translation which it probably is because we don't have enough public IPv4 addresses for every fictional office to have their own IP address.

In reply to a post by DaveySmith55fp:

Please explain what you ,mean by internal network?

In your mythical example Thompson Construction. As you are connected to one of their network devices on the LAN then they will at the very least have a record of your internal IP address and the MAC address of your network card, as said whether that’s WiFi or wired or whatever. They may have further security which would would require a login before they allowed you into the network, for example via a portal or other means that could directly identify you.

To the upstream ‘ISP’ none of these details are visible, you are but one of very many connections connected via Thompson Construction’s router(s) and firewall(s).

What is the background / nature of your question - is this for practical understanding, are you trying to solve a problem. Is it homework? What exactly?

Hmmm .

If for example I am in a building containing 150 offices. They are all serviced by the same ISP. Each floor has a router servicing 30 offices each.
I log on through Thompson Construction wifi network using their password. I know the ISP can see my IP address is logged on to their system but can they know I am logged on through through Thompson Construction or do they just know I am logged on via a specific router/access point?

Do you know someone who has an HR issue?

Can ISP normaly nope. I said normaly if network is managed by ISP who also network infrastructure provider (ie network admin router/swich/etc) then yep.
Now there are issue under data rights at work ie DPA/EPDPC/GDPR. But saying that an employer can (if done correctly/legaly) snoop on there network. They can set up browser so can view all traffic even if encripted (HTTPS TLS/SSL).
(I am NOT legal expert)

Edited by amiga_dude (Thu 29-Jul-21 11:34:26)