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)

In reply to a post by amiga_dude:

They can set up browser so can view all traffic even if encripted (HTTPS TLS/SSL).

Not often in UK/Europe unless staff are told and asked to sign/agree terms. If staff are using their own computer then hard to do.

Solution to all of this is to use your own VPN !

In reply to a post by amiga_dude:
They can set up browser so can view all traffic even if encripted (HTTPS TLS/SSL).

Not often in UK/Europe unless staff are told and asked to sign/agree terms. If staff are using their own computer then hard to do.

But idea must be in formal (employment) contract is incorrect. If there notice page when you sign in to network (T&C) that would do. Also they could be legitamite reasion why business decideds to do snooping without inform you/consent, ie industrial espionage/crime protection. But business that really need to worry about things like industrial espionage most likely have it in part of employment contract(s).

In reply to a post by jchamier:

Solution to all of this is to use your own VPN !

Now for VPN. It will not help you, if the browser had been set up correctly it will now not work outside business network "Thompson Construction". As the browser would be set only allow there own Certificate Authority (ie "Thompson Construction") to work.
If not website own key isn't sign by the business own Certificate Authority of "Thompson Construction" then it would not allow to view the page.
Another way of explane it is by using own VPN connection there is nothing to be able to sign for website using Certificate Authority of "Thompson Construction". As such every webpage is now blocked. Just because your using VPN that is not being controlled by "Thompson Construction".

(I am NOT a legal expert)

Don't forget the point Pheasant raised. The whole opening post is an "example" scenario. In my initial reading of it I forgot the first three words once I got to trying to work out how it was configured. The whole thing seemed very off to me at the time, with my idea of serviced offices being the only possibility I came up with.

The more I think about it the less sense it all makes. 150 offices, 30 per floor, with a router on each floor, all from the same ISP. Really? Is that one connection or five connections, and who is the "customer"?

For them all to be the same ISP then the manager of the building has to be the customer. Otherwise the probability of the scenario is incredibly low. I think Pheasant asked the right questions at Thu 29-Jul-21 06:59:10.

Edited by pluralist (Thu 29-Jul-21 13:05:13)

It does sound like the real world example of this would be a building that rents out space to various businesses or individuals and as part of that rental provides Internet access (there are I think a number of examples of this these days).

In that case the building management would be responsible for the Internet connection and could put any level of management on the link that would give them information about what is being done. They may even block VPNs or use proxy servers that do full logging of all access including SSL inspection. Or they might just provide a free for all Internet link.

Whoever has the ISP contract would have legal responsibility for everything that is done over it and if providing it to so many 3rd parties they most likely would need a fair amount of logging in order that if something illegal occurred they could provide information to the authorities as to who was the perpetrator.

So, whilst the ISP wouldn't see the detail of what is happening on the internal network it is highly likely that the building management would be able to and indeed would hand over that information on presentation of a court order or other legal means of request.

EDITED: To correct a stray "un" as identified by Pluralist.

Edited by ian72 (Thu 29-Jul-21 14:27:46)

Regus used to offer something like this years ago to their office tenants but it was £££ for what bandwidths were on offer. We used to sort out our own connections, which they grumbled about (as they obv. want to tie you into as many revenue generating schemes as they can) but ultimately let us do as we pleased.

In reply to a post by ian72:

So, whilst the ISP wouldn't see the detail of what is happening on the internal network it is highly unlikely that the building management would be able to and indeed would hand over that information on presentation of a court order or other legal means of request.

I think you mean "... it is highly likely that the building management would be able to ..."?

In reply to a post by pluralist:

Who do you pay for your broadband?

The question, seeing as the OP was hypothetical, should have been "who would be paying the ISP?"

The reason I asked being to clarify that the building management would be the LAN service provider, not just the infrastructure hardware provider.

Edited by pluralist (Thu 29-Jul-21 14:07:10)

You are right, I did indeed, will edit it to correct.

That's exactly what I was thinking.
My company used to be in serviced offices and there was a single connection shared by every company in the building.
Each company would run their own router and Wi-Fi and then the WAN side of their router would connect to the building managements router with each company having their own separate VLAN

Thanks
Dan

In reply to a post by pluralist:

The more I think about it the less sense it all makes. 150 offices, 30 per floor, with a router on each floor, all from the same ISP. Really? Is that one connection or five connections, and who is the "customer"?

For them all to be the same ISP then the manager of the building has to be the customer. Otherwise the probability of the scenario is incredibly low. I think Pheasant asked the right questions at Thu 29-Jul-21 06:59:10.

One of my customers rents a unit, part of the set up is a connection through the landlords internet connection, I'm not sure of the full terms, but I know there are about a dozen units all connected up the same, they have what appears to be a standard ethernet cable coming in to unit and they plug in their own router, and have no separate ISP account, I know this as I gave them one of my spare TalkTalk routers as the Netgear one they where using was rubbish.

In reply to a post by ian72:

It does sound like the real world example of this would be a building that rents out space to various businesses or individuals and as part of that rental provides Internet access (there are I think a number of examples of this these days).

We use a few of these, and if the building supplied Internet tried any of the activities, we would terminate and go to their competition.

Might be useful in a university hall of residence shared internet to "police" the network, but very unlikely in a shared working space. Especially blocking VPNs (e.g. corporate, rather than home user).

This is closest to the scenario I was asking about,. Except building management are not the ISP provider.

The building is rented office spaces to small businesses and the renting and day to day running of the building is handled by management.

However the ISP provider for the building rents one of the offices and all tenants have the option of purchasing internet connectivity from this ISP. They do not have to but pretty much everyone renting office space there does. Vpn connections are allowed.

Sorry for my lack of clarity.

So the answer to my earlier question:

In reply to a post by pluralist:

Who do you pay for your broadband?

Is the tenant of the office.

So the ISP does know you have logged in through the mythical Thompson Construction.

I hope this thread by you is entirely legit, as it's a very strange question to be asking, and whatever the real world setup is that you are supposed to know the Thompson password.

OK well that’s certainly a lot clearer than the invented scenario in your OP!

Basically your neighbouring tenant in a shared space office is reselling you some or all of their pipe. Are they an actual comms provider or are they just some Joe’s doing this on the side?

You can name names I’m sure it’s not against the law.

So the whole question is who manages the network itself. If it is all managed by this other tenant then they could potentially see who is doing what. It is possible that they get an ISP to manage it all for them in which case the ISP might be able to see who is doing what.

In normal circumstances the ISP will see that traffic has come via the Internet link and where it is going to. They would consider the entity renting the circuit to be responsible for all traffic. The renting entity therefore needs to be able to back off liability if there was a court order or similar - normally that would be done by them being able to identify who is responsible for traffic over the connection. Depending on how the other networks connect in this might just identify a single router/firewall that the traffic is coming from or it could identify the individual device - but that is all down to network design.

There is no simple generic answer as there are a number of ways this could be configured and a number of options for who would provide the management and logging.

In reply to a post by ian72:

There is no simple generic answer as there are a number of ways this could be configured and a number of options for who would provide the management and logging.

Contract or other terms of service from the "network provider" should reveal what's what. if they don't and the OP is a director or manager of the company that's getting service from them, then I'd be asking some questions - as you would doubtless with any supplier thats selling you their wares or service.

Otherwise this is probably a bit of a fishing expedition, there's countless variables as you note that makes it pointless.