How can two home networks interfere with one another?

[StewartR]

There is a thingy in some routers which sets wireless devices to being discoverable. There is also the wireles setup and DNLA type gubbins that would allow a device to connect too easily. If could be another near neighbour that has connected. I always change my router names so they aren't the default gibberish so it's obvious to anyone else it's not theirs.

I don't think that's the issue. My WiFi router is discoverable - I saw it listed on my neighbour's laptop. But it's password protected so even if he can see that it's there he shouldn't be able to connect to it.

 

[StewartR]

If you want to stop it then you set your router to only allow your Mac addresses of your known devices to connect. I would also contact plusnet support and ask them whether other customers have the same issue as it could be a total foul up with the firmware on the router.

That doesn't solve the problem. The problem is that my devices are connected to my neighbour's network. (And, yes, his are connected to my network. But I'm not the one who's complaining about it.)

 

[Andy Taylor]

This is certainly intriguing, the thing to remember is that there has to be a logical (if improbable) explanation. The only way to get to the bottom of this is by a process of elimination.

I would start by reducing your network down to the bare minimum - Router and wired computer. Disable wireless on the router. Start adding wired devices one by one. Reset the power line adapters and make sure they are secured etc.

You will find the cause.

 

[ecoleman]

i would guess that the 192.168.1.1 device is a router. Do you know what IP address your router uses.
Also do you know what range of IP addresses your routers DHCP dishes out? It seems strange that your devices are allocated IP addresses from 1.65 and the jump into the 1.200 range.

The neighbours devices all seem to be 1.2, 1.3 etc.

You also have a 192.168.1.99 from TP link and I wonder if this is some sort of wifi booster or bridge that the neighbour has. If somebody has setup the network for him, he may not be aware he has it.

Edit, just seen you router is set at 192.168.1.254, so any bet the 192.168.1.1 is next doors router as this is a default IP address for most routers.

Have you tried simply changing your wifi password and ensuring you don't have any guest networks enabled.

Also remember that the router will be listing anything where the IP lease is still active, FING scans the network for devices that are currently live. Most DHCP servers will allocate an IP address with at least a 24 hour lease.

 

[Fodrigal]

That doesn't solve the problem. The problem is that my devices are connected to my neighbour's network. (And, yes, his are connected to my network. But I'm not the one who's complaining about it.)

That might solve the issue if one of your neighbours devices is attaching to your network through a shared connection somewhere

If you restrict your network by MAC address at least you'll be able to narrow who owns the device that's causing the issue

For your neighbour to see all your devices his laptop must either be sending requests across the network to discover them, or getting them sent by a device on your side

If you have suspect devices you can always get wireshark installed to monitor the traffic as well, might help you identify what you've got connected.

 

[StewartR]

...you router is set at 192.168.1.254, so any bet the 192.168.1.1 is next doors router as this is a default IP address for most routers.

Agreed.

Have you tried simply changing your wifi password and ensuring you don't have any guest networks enabled.

Changing the WiFi password won't achieve anything because my neighbours don't know the password. And I don't have any guest networks enabled.

 

[Alastair]

Changing the WiFi password won't achieve anything because my neighbours don't know the password.

Just do it. Humour us.

 

[ecoleman]

Changing the WiFi password won't achieve anything because my neighbours don't know the password. And I don't have any guest networks enabled.

Maybe they don't, but something is connecting to your network and unless they have an Ethernet cable connected, wifi is the only way your networks can be bridged.

If your neighbour does have a device that is connected, changing your password should prevent it from connecting again.

We're just making suggestions, it's not easy to diagnose an issue like this without seeing how every is physically configured.

I'd also have a look at your router configuration and disable WPS if your router has that facility.
http://www.howtogeek.com/176124/wi-...-is-insecure-heres-why-you-should-disable-it/

 

[peej1977]

I don't know if it's been suggested but you could try seeing what wifi channel both of your routers are using. If they are clashing then it's possible device discovery could be "seeing" the devices by MAC address showing them but if his devices aren't showing up on a network scan then it's unlikely either of you has access to each other's networks, just that your wifi channels are clashing. Channels clashing is the single biggest wifi issue especially in urban areas. I've had to hard code mine so it doesn't interfere with my neighbours one.

 

[Ploddles]

Changing the password COULD help even if he doesn't know it.

It is only a small coincidence but at any point have you pressed the WPS button on your router? Even if you haven't done it intentionally to join 1 of your wifi devices to your network, if it has been pressed, even accidentally, at the same time (usually within 2 minutes) as he has pressed it on any of his devices, including the router then the 2 devices would connect without him having to enter a password.

As I said, it would be exceptionally coincidental if it happened at the same time but if anything is pressing the button in the 2 devices WILL connect without the password. A bridge between the 2 networks could then exist.

EDIT:-

I see Elliott mentioned WPS as well, we must both have been typing at the same time.

 

[ecoleman]

I don't know if it's been suggested but you could try seeing what wifi channel both of your routers are using. If they are clashing then it's possible device discovery could be "seeing" the devices by MAC address showing them but if his devices aren't showing up on a network scan then it's unlikely either of you has access to each other's networks, just that your wifi channels are clashing. Channels clashing is the single biggest wifi issue especially in urban areas. I've had to hard code mine so it doesn't interfere with my neighbours one.

Overlapping wifi channels will cause interference but shouldn't allow you to see each other's networks.

 

[peej1977]

I haven't read the entire 5 pages (I'm on my phone) but aside from seeing the list of devices are they actually able to access any of the devices? Beyond just seeing the names of them?

 

[ecoleman]

This is what I would do.

1. Change router wifi password and disable WPS.
2. Disconnect everything wired and wifi devices) and reboot the router.
3. Give it a few minutes and scan the network with FING.
4. Attach each wired device one by one. Allow a minute or two and rescan the network with FING.
5. If no neighbour devices are found repeat steps 4.

6. Move on to the wifi devices and repeat steps 4 and 5 for each.

If you see the neighbours devices pop up then you have hopefully found the culprit device that is allowing the bridge (maybe an ad-hoc network)

 

[StewartR]

Right, I've had enough for today so I'm going to try to get on with my life for a couple of hours.

I want to work out why this is happening rather than just change setting and hope that cures it. So with that in mind I'd be grateful if anybody has any insights into the following issues.

1. My router lists a bunch of devices which it says are connected to IP addresses where the final number is very low - 192.168.1.2, ...1.4, ...1.5, ...1.7, etc - and it looks like these could be our neighbour's devices. But why isn't Fing spotting them when it scans our network? What mode of connection could there be, which would be visible on the router but not visible to Fing?

2. I just discovered a little black box sitting next to the router which (I think) connects via WiFi to our smart electricity and gas meters. So that's another two devices which are connected to our network somehow, but I haven't been able to positively identify them. Pus we have a controller for our solar panels which is remotely accessible, so that must be ion the network somehow too. Maybe these are three of the unidentified devices. I'll get the MAC addresses from the suppliers tomorrow to check. But this leads us into the whole Internet Of Things area, and of course IOT also stands for Internet of Targets because so many of these devices are insecure. Here we seem to have three devices of basically unknown pedigree which are attached via WiFi to our network. Is that cause for concern? Does this point the finger at the rogue connection coming via potentially unsecured WiFi? If so, what action could I take, given that I can't disable the smart meters or the solar panels?

3. The 'devices' page on my router lists which port each device is - or has been - connected to. Some of them connect via WiFi and some via the various Ethernet ports. But all of the unidentified devices, and all of the devices which are definitely my neighbours' (eg the 'Bradfield-Sony' laptop) are connected via Ethernet Port 1. That's the port on the router which connects to the powerline adapter, and thence to our desktop PC (no WiFi capability) and out Humax set top box (no WiFi capability). Does this point the finger at the rogue connection coming via the powerline adapters? If so, how?

See you tomorrow, folks! And thanks again for all the help so far. We'll get to the bottom of this.

 

[srichards]

Yes. I'd think that points the finger fairly firmly. Best test would be to move powerline thing to another port and see if the port changes with it when you check to see what is connected.

 

[Sejanus Aelianus]

All of them apart from the Humax box communicate via WiFi. What does that tell us?

The question is whether one of them is acting as a gateway to your network. The Loxone is the obvious candidate to investigate first as, from the description, it's probably set up to accept connections from other devices, so it may be allowing your neighbour's devices to see your network and you to see his. It might not be permitting access, and you've told us that your neighbour can't access your devices.

You want to close that hole, wherever it is, as a black hat could easily find a way onto your systems through it.

 

[onomatopoeia]

3. The 'devices' page on my router lists which port each device is - or has been - connected to. Some of them connect via WiFi and some via the various Ethernet ports. But all of the unidentified devices, and all of the devices which are definitely my neighbours' (eg the 'Bradfield-Sony' laptop) are connected via Ethernet Port 1. That's the port on the router which connects to the powerline adapter, and thence to our desktop PC (no WiFi capability) and out Humax set top box (no WiFi capability). Does this point the finger at the rogue connection coming via the powerline adapters? If so, how?

It seems to, yes, and it suggests the neighbours have a powerline adapter.

This assumes the loxone can't act as a bridge in some way, but a quick look at their site looks like it contains advertising shiny rather than useful technical information.

 

[EightBitTony]

I want to work out why this is happening rather than just change setting and hope that cures it.

You keep saying that as a way to not making any changes - but one way to isolate the cause of the issue is to reduce the problem to the fewest parts. I'll give you an example, two weeks ago, I started seeing intermittent network issues on devices on my network. Smart TV, couple of consoles, few PC's, usual set of android devices, couple of routers.

It was intermittent, and didn't seem to be doing anything logical.

I went through everything for about 4 hours checking settings, restarting the routers, etc. Nothing helped.

In the end, I unplugged everything, and plugged things back into the network one at a time, as soon as I plugged the TV in, the network crashed. My (android based) TV had a crashed network stack, such that it was crashing the ADSL router. I found that by a process of starting with nothing connecting and then adding devices. I *thought* the problem was intermittent, but it wasn't, it was just once crashed, the router behaved oddly. But, once I identified the TV, plugging it in crashed the router every time. A full power cycle of the TV resolved the issue (welcome to the future).

So I strongly suggest you do as advised, unplug everything from the network, refresh the list of connected devices. If your neighours devices still show up - the problem is the wifi router, if not, add devices one at a time until the other stuff shows up - and then you've found your culprit. *Then* you can start working out why it's behaving badly. You have too many devices to just guess at which one is broken.

 

[EightBitTony]

It seems to, yes, and it suggests the neighbours have a powerline adapter.

This is my strong belief too, but they probably aren't called that, they'll be called broadband extenders, or BT Home Hub Extenders, or something like that which is why the neighbour didn't realise what was being asked.

 

[StewartR]

One more thing. I haven't reviewed any contributions since post #86; I will do tomorrow. But after I'd "downed tools" my mind went back to something my neighbour said earlier, which subconsciously had been bugging me. And I think it could be very important.

He said that he'd had this problem for a while, but it stopped some time around September last year, and it's only recently started up again. He was pretty sure about the timing, and, although he's elderly, he's still playing with a full deck of cards. September was when our major building project started, and he said he assumed that we'd put our computers into storage for the duration of the works. But we hadn't - we've moved things around a bit as the building work has progressed, but we've had to keep our IT gear available because we both sometimes work from home. I couldn't make any sense of his September observation at the time, so I just put it to the back of my mind.

But. Moving things around as the building work has progressed has involved some important changes to our network topology.

Pre September: Router in study upstairs. Desktop PC in study, connected directly to router. TV set top box in lounge downstairs, connected to router via powerline adapter.

September to April: Downstairs uninhabitable. Router in study upstairs. Desktop PC in study, connected directly to router. TV set top box in bedroom, not connected to the network.

April onwards: Router in new study downstairs. Desktop PC in bedroom upstairs, connected to router via powerline adapter. TV set top box in new lounge downstairs, connected to router via powerline adapter.

See it? Prior to September, when our neighbour experienced network problems, we were using powerline adapters. Since April, our neighbour has been experiencing the problems again, and we've been using powerline adapters again. But in the intervening period, when he had no problems and assumed we weren't using any computers, we weren't using powerline adapters.

Could this be the smoking gun?

I think I need to talk to him again tomorrow and ask him how certain he is of these timing issues. And I think I need to ask him to show me how everything in his house is connected, just in case he is using powerline adapters but wasn't aware of it. (For example if his son installed them without explaining in detail how they work.)

More news as it comes in.

 

[EightBitTony]

I think I need to talk to him again tomorrow and ask him how certain he is of these timing issues. And I think I need to ask him to show me how everything in his house is connected, just in case he is using powerline adapters but wasn't aware of it. (For example if his son installed them without explaining in detail how they work.)

Show him a powerline adapter - ask him if he's got anything plugging into a power socket which looks similar or has a network cable plugged in. BT sell 'broadband extenders', and other branded products which are never referred to as powerline adapters.

 

[seriousrikk]

Show him a powerline adapter - ask him if he's got anything plugging into a power socket which looks similar or has a network cable plugged in. BT sell 'broadband extenders', and other branded products which are never referred to as powerline adapters.

So do talk talk

I know when my dad had the bt vision box that came with a powerline type adapter to connect it to the router.

 

[landwomble]

I bet a fiver you both have power line networking kit.
If this was happening to me I'd run the power line discovery tool which will pick up all power line adaptors in the subnet. ID yours by powering off and back on. Then change the encryption key on yours.

 

[Furtim]

One more thing. I haven't reviewed any contributions since post #86; I will do tomorrow. But after I'd "downed tools" my mind went back to something my neighbour said earlier, which subconsciously had been bugging me. And I think it could be very important.

He said that he'd had this problem for a while, but it stopped some time around September last year, and it's only recently started up again. He was pretty sure about the timing, and, although he's elderly, he's still playing with a full deck of cards. September was when our major building project started, and he said he assumed that we'd put our computers into storage for the duration of the works. But we hadn't - we've moved things around a bit as the building work has progressed, but we've had to keep our IT gear available because we both sometimes work from home. I couldn't make any sense of his September observation at the time, so I just put it to the back of my mind.

But. Moving things around as the building work has progressed has involved some important changes to our network topology.

Pre September: Router in study upstairs. Desktop PC in study, connected directly to router. TV set top box in lounge downstairs, connected to router via powerline adapter.

September to April: Downstairs uninhabitable. Router in study upstairs. Desktop PC in study, connected directly to router. TV set top box in bedroom, not connected to the network.

April onwards: Router in new study downstairs. Desktop PC in bedroom upstairs, connected to router via powerline adapter. TV set top box in new lounge downstairs, connected to router via powerline adapter.

See it? Prior to September, when our neighbour experienced network problems, we were using powerline adapters. Since April, our neighbour has been experiencing the problems again, and we've been using powerline adapters again. But in the intervening period, when he had no problems and assumed we weren't using any computers, we weren't using powerline adapters.

Could this be the smoking gun?

I think I need to talk to him again tomorrow and ask him how certain he is of these timing issues. And I think I need to ask him to show me how everything in his house is connected, just in case he is using powerline adapters but wasn't aware of it. (For example if his son installed them without explaining in detail how they work.)

More news as it comes in.

From what you've said in previous posts, the bridging is occurring on the wired side of your network (as they are presenting on the wired interface in the router), so you can ignore the Wifi side for the moment.
With the added information from this post, it points the finger at (a) the neighbour having a similar un-encrypted powerline adaptor (as others have stated, they can be called boosters, etc), or (b) your set top box (as it was also disconnected from the network when the issue disappeared), is acting as the bridge.

Because it's easy, I'd disconnect the set top box and see if that fixes the issue, at least then you've eliminated one possibility.
I'd then setup encryption on the powerline adaptors, although I'm surprised its not on there by default - the early ones we used were open, but the ones from a couple of years ago were all encrypted from the factory.

 

[ecoleman]

This is my strong belief too, but they probably aren't called that, they'll be called broadband extenders, or BT Home Hub Extenders, or something like that which is why the neighbour didn't realise what was being asked.

And I'll put money on it having the IP address 192.168.1.99 and it being a TP-link

Have a look at this.
http://www.tp-link.com/en/faq-259.html

Any bets if you run the top link utility you will see an unknown power line device there.
Then you just need to change your passwords for your devices and change your private network name.
Don't change the neighbours device.

 

[Jelster]

I had a problem with my neighbour some how getting onto my network so I blocked their devices at MAC level on the router. Rebooted it and it was sorted.

 

[DeadpanDodo]

I think the neighbours TalkTalk set top TV box (made by Huwai) is connected by homeplugs, although he doesn't realise it. The standard homeplugs issued by TalkTalk for use with their TV package are currently TPLink manufactured.

I am interested in this thread as I noticed an unknown smartphone momentarily connect to our network last weekend. We also have a combination of WiFi, ethernet, and homeplug conncted devices. I was surprised and a little alarmed, but have been unable to see it appear again.

 

[landwomble]

I had a problem with my neighbour some how getting onto my network so I blocked their devices at MAC level on the router. Rebooted it and it was sorted.

That's not really fixing the oriblemz, any new devices will still get on your network and MAC addresses can be changed. You still have a security problem.

 

[StewartR]

Have a look at this.
http://www.tp-link.com/en/faq-259.html

Any bets if you run the top link utility you will see an unknown power line device there.

You lose. Sorry.

I've physically inspected my powerline adapters and confirmed their MAC addresses. I'm running the utility on the PC in the bedroom, on adapter #1, and it can see adapters #2 and #3 - but nothing that I can't identify.

 

[landwomble]

Having spent quite some time futzing about with that utility I would definitely not rely on it giving a full list every time it's run.
Also there are several different manufacturers of power line kit with variable interoperability.
Perhaps we put it down to witchcraft and move on... ;-)

 

[DeadpanDodo]

As one of the suspect unknown devices is a TP link product, neither you or your neighbour have one of these installed by any chance?

http://www.tp-link.com/en/products/details/TL-WR702N.html

Incredibly useful and versatile bit of kit that can be used as a wireless access point, repeater, client, or wifi bridge, depending on how it is configured. It can be used to add wifi to any device that has an ethernet port, eg older smart TVs, or alternatively to create a wifi hotspot from an ethernet connector (perfect for use in hotel rooms or student accommodation which provides only wired ethernet but not wifi).

However if not properly secured when used as a repeater or bridge, it would make your network very vulnerable.

 

[admirable]

Are you in a detached house, how far away is the old guy?

 

[ecoleman]

You lose. Sorry.

I've physically inspected my powerline adapters and confirmed their MAC addresses. I'm running the utility on the PC in the bedroom, on adapter #1, and it can see adapters #2 and #3 - but nothing that I can't identify.

Okay, but humour us and change the passwords and network name on your devices and relink. There seems to be lots of debate here but not a lot of actually doing anything to eliminate causes.

 

[ecoleman]

As one of the suspect unknown devices is a TP link product, neither you or your neighbour have one of these installed by any chance?

http://www.tp-link.com/en/products/details/TL-WR702N.html

Incredibly useful and versatile bit of kit that can be used as a wireless access point, repeater, client, or wifi bridge, depending on how it is configured. It can be used to add wifi to any device that has an ethernet port, eg older smart TVs, or alternatively to create a wifi hotspot from an ethernet connector (perfect for use in hotel rooms or student accommodation which provides only wired ethernet but not wifi).

However if not properly secured when used as a repeater or bridge, it would make your network very vulnerable.

That's what I suspect it is (that or similar). Guaranteed the neighbour has a power line wifi extender or just some power line devices that have linked to Stewart's.

 

[terrific]

You lose. Sorry.

I've physically inspected my powerline adapters and confirmed their MAC addresses. I'm running the utility on the PC in the bedroom, on adapter #1, and it can see adapters #2 and #3 - but nothing that I can't identify.

Just a thought,
It looks like the TP link utility implies there is no password set for the home plugs? They should have a push button to "encrypt" on each unit.

 

[2blue4u]

Powerline adapters shouldn't work beyond your in-house leccy meter. But they can although it is RARE. Even if this issue is caused (in part) by powerline plugs, discovering this isn't going to solve the problem.

The problem is that you are both using 192.168.1.* This, plus a (lack of) security issue.

Change your router's address from 192.168.1.254 to 192.168.0.254 (last number can be anything 1-254).

 

[landwomble]

Just a thought,
It looks like the TP link utility implies there is no password set for the home plugs? They should have a push button to "encrypt" on each unit.

Yes, they *in theory* come in pairs with a unique encryption key and you can then add more to the mix by pressing the sync button on the "master" and then on the "slave" within a few mins of each other. However they all have a little web server built in where you can change this. Now, if it were me, I'd have ripped them out of the wall within 30 seconds of noticing my network was bridged without my permission to a neighbours and reset this myself to a new shared key.

At the moment, anything they do on their network can be attributed to you and vice versa. I'm sure your neighbour's reputable but if they were to download something questionable then you could well be on the hook for it...

 

[StewartR]

Just a thought,
It looks like the TP link utility implies there is no password set for the home plugs? They should have a push button to "encrypt" on each unit.

They do have push buttons to set up pairing when first connected, and they do have passwords. Here's the plate on the back of one of the units.

When I set up the powerline adapters I used the push button to pair them. In theory that means they have set up a private network and my neighbours' powerline adapter should not be able to talk to them. In practice it seems that may not be the case. I will use the TP-Link utility to explicitly create a private network and see whether that makes a difference.

 

[StewartR]

OK, what I'm going to do when I have some time at home and my neighbour is around and able to co-operate.

1. Check that my router can see his devices and that his router can see mine.
2. Switch my WiFi off and see whether that makes a difference.
3. Disconnect my powerline adapters and see whether that makes a difference.
4. Switch his WiFi off and see whether that makes a difference.
5. Identify his powerline adapters - I think it's likely he has some, even if he isn't aware of it - disconnect them and see whether that makes a difference.

The key thing I need to do is prove to him that we know what is causing the problem, so that he can have confidence when we've fixed it that my devices aren't messing up his network.

I think what will happen is that we will establish that it is the powerline adapters which are causing it. If that's the case, my next step is to explicitly set up a private network for my powerline adapters and see whether that fixes the problem.

 

[2blue4u]

*Cough*

Solution >

The problem is that you are both using 192.168.1.* This, plus a (lack of) security issue.

Change your router's address from 192.168.1.254 to 192.168.0.254 (last number can be anything 1-254).

Switch off/disconnect all devices. Change the modem/router address. Pour glass of wine. Plug everything back in.