How to find a router at an unknown location in a house?

171

I want to install a WLAN repeater in my father’s holiday house which he rents out to other people.

My father is a digital neanderthal and doesn’t know where his router is, therefore I cannot configure my repeater to this router.

Are there any tools that could help me find that router in the house? I know that there are tools that tell you which Ethernet cable is in use and where it points to, so I figured maybe there are tools that help me find my router?

By “tools,” I don’t necessarely mean software, I’m also thinking about a hardware tool. I tried just going around with my cellphone and searching in the area with the best connection to the network but didn’t find the router.

Edit: Due to some comments that wanted more information about the router: It's a normal ADSL/VDSL router which sends WiFi signals. Distributed by the market leader ISP in my country. It also can do WPS. Here's a link: https://www.swisscom.ch/en/residential/help/device/internet-router/centro-grande.html

Update: Very special. The WIFI Signal was from the router inside my fathers home which is right next to the holiday house. So the Router actually had two different WIFI Signals, with two totally different strengths. In the Holiday house, signal A which my father uses for private stuff had only one line strength on the phone while signal B had 3 to 4. I can't really believe that something like this even exists, but the supporter from the ISP told me that it is like this. I asked "really?" and he said "100%, I can see it in my system".

SimonS

Posted 2016-04-10T09:45:23.827

Reputation: 4 566

WPS should be optional as it isn’t available on all devices. // But anyway, what type of connection is it? DSL? Cable? Fibre? – Daniel B – 2016-04-10T10:05:47.307

78Unless your father lives in a mansion there can't be that many places to hide a router ;) Look on the outside of the house to see where the phone or cable connection comes in. Look on the other side of that wall. That's the most likely place. Probably in the cupboard with the electric meter etc ... – DavidPostill – 2016-04-10T10:46:45.377

18@DavidPostill david believe me, i looked at every square centimeter there is ;). maybe my father can make things invisible, i don't know. – SimonS – 2016-04-10T12:02:24.860

52Use circuit breakers to localize the router. – waltinator – 2016-04-10T14:24:40.340

2Sadly, most answers seem focused on using Wi-Fi. One of the questions (in the "question" section) was, "which Ethernet cable"... If you can find Ethernet cables, there are tools made by a company that has generated a seriously positive trustworthy reputation for its very laughable name: Fluke (Fluke Corporation, Fluke Networks). They are rather pricey, but can often tell you if something is on the other side, how far away it is (but I don't think can say which direction, if any, the cable curves). – TOOGAM – 2016-04-10T16:17:19.347

1Who was the router installed by? If it was the IPS, they could possibly have a record of where it is, or the person who installed it might remember where – Keith M – 2016-04-11T06:31:43.103

89Are you sure your father actually has a WiFi router and hasn't just been piggybacking off a neighbours open connection for years? – Paddy – 2016-04-11T11:02:32.347

Some ethernet equipment (like managed switches or LAN testing devices) can measure and display the length of the attached cable. I don't know how reliable it is, but it might help to narrow down the search radius. Maybe someone more competent would like to expand this into an answer?

– oliver – 2016-04-11T11:08:18.140

1@SimonS Are there actually ethernet cables going out from the router or not? You haven't stated explicitly. – LinuxDisciple – 2016-04-11T17:21:39.383

@DavidPostill It could be inside a wall

– Izkata – 2016-04-11T20:33:14.853

2@SimonS, although I'd want to know where the router is regardless...why do you need physical access to the router to set up a repeater? You could use the gauge suggested by gronostaj in reverse - find the place in the house where the signal is the lowest, and plug a repeater in there. Unless you want to run a wired repeater, or you need physical access to the router to log in or something? – Jake – 2016-04-11T21:07:46.757

maybe he's unknowingly connecting to the neighbors router. – the_lotus – 2016-04-12T11:22:37.387

2Where you able to locate the telephone connection of the house? And if so, why are you unable to track the cables? – André Stannek – 2016-04-13T15:05:58.310

2Correct me if I'm wrong, but asking for "tools" (hardware or software) is off-topic. – Pointer – 2016-04-14T15:05:22.550

1-1 for calling anybody a "digital neanderthal". There are ways to say that he's not confident with IT without being disrespectful. – fdierre – 2016-04-18T13:23:55.773

5@fdierre Meh, it's his own dad, and I think, clearly in jest.

OP, did you solve this problem? How did you do it, and where was the router? – Revetahw says Reinstate Monica – 2016-04-19T06:10:05.523

3I'm curious as to where you find it. – Celeritas – 2016-04-19T08:43:34.693

@Pointer This is a good on-topic question, "tool" isn't a prohibited word, here's your correction reference: How do I ask a question that may require recommending software? This Q fits the correct "How-To": "I have <problem-x> that I don't know how to solve. I've already tried X, Y, Z, but those programs don't work because this or that. How do I do this?"

– Xen2050 – 2016-04-19T18:19:34.373

This reminds me of a classic Bash.org post: <erno> hm. I've lost a machine.. literally lost. it responds to ping, it works completely, I just can't figure out where in my apartment it is.

– Iszi – 2016-04-19T20:18:30.663

2Any updates? Have you found it? – hamena314 – 2016-04-28T08:24:56.647

1@hamena314 Yeah, OP has posted updates. So mysterious! Why would it be inside the wall?? – Revetahw says Reinstate Monica – 2016-09-18T07:59:58.723

@Celeritas Check out OPs update. – Revetahw says Reinstate Monica – 2016-09-18T08:00:10.307

I helped relatives find mine recently and it was in a panel inside a closet. – Celeritas – 2016-09-19T00:02:45.317

The strong "signal A" was probably on the 2.4 GHz band while the weak "signal B" was 5 GHz. – I say Reinstate Monica – 2018-11-23T02:54:35.390

@TwistyImpersonator the weird thing is, that signalA was way too strong. The router was in house A, then comes a around 20m gap between house A and house B and i still had a good connection in house B. I know these routers, they are in many households in switzerland, and normaly they already have problems getting their signals through two rooms – SimonS – 2018-11-23T08:05:36.667

Answers

200

If you have a Android smartphone or tablet, you can use the WiFi Analyzer app. It has a screen dedicated to detecting proximity of access points:

Walk around the house and see where the signal is the strongest.

gronostaj

Posted 2016-04-10T09:45:23.827

Reputation: 33 047

I found an interesting app for your Windows Phone: https://www.microsoft.com/en-us/store/apps/wifi-analyzer-preview/9nblggh33n0n

(Didn't test it because I don't own a WP).

– Jesús Hagiwara – 2016-04-10T22:23:36.073

6@SimonS or use a laptop running such a program – barlop – 2016-04-11T02:15:37.927

41I have actually used this app for playing a variant of the "hiding" game with the kids. One hides a spare router somewhere in the house, and the other ones try to find it. The gauge is actually quite helpful and this app can be configured to scan once a second. We had some fun with it. – Marcel – 2016-04-11T07:22:11.787

1I love this app, it's one of the first I installed when I switched to Android and it gets used at least every couple weeks... and it works great for this situation too – Taegost – 2016-04-11T17:09:55.297

3Note that there are somewhat limited cases where this may not work - if your router was on the opposite side of a lead wall from you, your gauge may be quite low despite how close you are to it. Similarly, a microwave being on could mess with the signal as well. Although I doubt your father has lead walls and humongous microwaves...if you really can't find it, I'd suggest having the app open and walking around the ENTIRE house - even if walking closer to a corner doesn't seem to yield anything, walk all the way to that corner, just in case. – Jake – 2016-04-11T21:04:25.693

2On a mac, you can just hold down the option key and click on the wifi icon in the menu bar. A bunch of extra info will show up among which is the signal strength. – BonsaiOak – 2016-04-12T19:57:52.050

4I'm constantly losing my router, so this tool is indispensable for me. – Darth Egregious – 2016-04-15T17:17:44.687

1@Marcel That's fantastic, haha. – underscore_d – 2016-04-19T10:42:30.623

@user973810 Are you joking? It could be serious, if it was a battery powered 4g router and you were carrying it around with you like a phone. – Revetahw says Reinstate Monica – 2016-04-22T16:58:15.243

@gronosta, How does this app work? – Pacerier – 2018-03-11T13:04:09.057

@Pacerier It shows a list of Wi-Fi networks in range and lets you select yours, then shows the strength of signal as you walk around the building. It also plays sounds so that you don't have to look at the screen all the time. – gronostaj – 2018-03-11T16:54:01.667

208

You are going to laugh, but I was in the same situation. I could not find my mother-in-law's router as the cable company had installed it.

When my nephews came over they wanted to use WIFI on their Samsung Tablet. I told them that the WIFI code is on a sticker at the bottom of the router. They turned the whole house upside down, and found the router on a top shelf in the cupboard. I have no idea why it was placed there, maybe for reception. The wire running to it went through a wall, so it was obviously not an easy place to install. That technician really gave it his best.

So find some kids with a tablet and invite them over. They'll find the router if that is what stands between them and Facebook.

dotancohen

Posted 2016-04-10T09:45:23.827

Reputation: 9 798

19I recommend only using previously-known children. – Raystafarian – 2016-04-19T07:41:23.703

7@Raystafarian "Mooom, that man from the big house on top of the hill has invited us over. He says we can use use his WiFi as much as we want if we find his antenna box... Can we go?" – Revetahw says Reinstate Monica – 2016-04-22T16:14:20.227

150

Barring an obvious wire leading to it, then searching by WiFi signal strength should be good too. But not the "walk around blindly with a strength meter" approach, use an app that will map it for you.

ekahau Heat Mapper

It can make a map for you, that should give you a better idea of which corners to be concentrating your search in. It's for Windows, How-To Geek has a little guide about it. They say it's "essentially the free version of the multi-thousand-dollar Ekahau SiteSurvey."

The best part: It may find the router for you.

once we finished walking the entire map, HeatMapper pinpointed the location of the two access points within our office with uncanny precision. Look at the red arrows on the map below:

There are some Android/iPhone apps that should be similar too, try searching for one that works on your device. Maybe Telstra Wi-Fi Maximiser (for Android), here's it's screenshot:

My first ideas were to:

I'd just follow the house wiring, starting from where they enter the house, and checking wherever the main cable or telephone "junctions" are, you didn't say if it's telephone/dsl, or tv (coax) cable, or pure network cable or fiber optic, but they all enter the house from somewhere. Unless you've got all underground utilities... but they probably don't enter through the basement, or "tube" would still come up from the ground somewhere outside the house.

If some technician installed the router / network cable recently (they weren't built into the house originally) then try looking around the "main" tv or telephone areas, high & low anywhere within reach, check for mystery power cords plugged in around there and follow them.
Phone the internet provider and ask them where they installed it. Maybe most of the houses in the area have a "standard" layout, or their installers always put them on the floor under tv's, or in the attics or someplace unexpected. Or they may have been good enough to take note of where it is in that house.

Xen2050

Posted 2016-04-10T09:45:23.827

Reputation: 12 097

How does this app work? – Pacerier – 2018-03-11T13:05:29.567

@Pacerier I don't know all the details, but I'd imagine they use the signal strength measured from different points to guess a circle of equal strength signals, then extrapolate to where the AP is probably located. Similar to locating a cell phone from it's signal strength to towers... – Xen2050 – 2018-03-13T04:16:01.240

You can use airodump-ng to scan for wireless networks. Once you see the network you're interested in, close and reopen airodump-ng with the arguments --bssid ... and -c ... corresponding to the BSSID and channel of the network, that way it won't waste time scanning other channels and will give you better update rate.

Now just walk around with the laptop and pay attention to the "PWR" column. The closer the number is to zero, the closer you are to the AP.

André Borie

Posted 2016-04-10T09:45:23.827

Reputation: 974

You can restrict search range by cut off electrical fuse for each room (if available ) so the wifi will turn off and you can localize room.

Alberto

Posted 2016-04-10T09:45:23.827

Reputation: 389

20The router could be powered from one room, while being in another - like a commenter said they found a router inside a cupboard with holes drilled. And old houses sometimes have very weird fuses, like two rooms on different floors sharing a fuse, one outlet in each, crazy stuff. – Xen2050 – 2016-04-10T21:47:56.847

3To give an example, I lived in a place where the wall outlets were on one fuse, while the ceiling outlets (for lamps) was on another. – Kristian – 2016-04-11T12:45:02.260

3I understand these situations and this was just a way to restrict the search range. Although I believe if you know a little about electrical circuits in house you can find the router. – Alberto – 2016-04-11T13:57:27.583

4@Xen2050, then this solution provides the bonus of learning oddities of how your house is wired. – user1717828 – 2016-04-12T09:39:59.577

1@Xen2050 - There were often good reasons for wiring a house like this. If all the outlets in a single room were on the same circuit, then a person using electricity in that room is more likely to overload that circuit and blow a fuse, or even risk an electrical fire. If each circuit is distributed all over the house, it's less likely that all the outlets on any circuit would be in use at once, giving less chance of overloading. – Darrel Hoffman – 2016-04-12T17:57:09.657

6@Xen2050 A corollary is that if each circuit is distributed all over the house, it can complicate your intentional efforts to avoid overloading a single circuit - "The A/C, dishwasher, and laundry are all running, and someone is using a blow dryer in the front bathroom. Which outlet can I plug the vacuum into? And do I need to warn anyone not to use the microwave right now?" – Dan Henderson – 2016-04-14T20:04:02.977

2@Kristian: this is a fairly standard setup (at least in France). The rationale, I guess, is to be able to use the room should one of the fuses fail. – WoJ – 2016-04-15T06:57:49.507

3@Kristian That is "to code". Lights have to be a different branch circuit from outlets, and you can't power outlets daisy chained off of light outlets, or vice versa. I also don't think this answer is good because 1 circuit in many cases (for example) is going to shut off the whole upstairs, large parts of the downstairs, or in the case of a kitchen/bath, 1 subset of receptacles there. Sure you could find if its upstairs or downstairs, but as far as pinpointing what room its in, this answer won't be accurate for 90% of the homes out there, especially the old/rennovated ones. – dhaupin – 2016-04-15T14:38:18.363

Along the lines of @dhaupin's comment, I know for a fact this would not work where I live, since the circuits connected to each breaker have a casual relationship with the actual floorplan, at best. – Todd Wilcox – 2016-04-15T15:21:56.900

@ToddWilcox Mine too man. Causal relationship is a nice way to say it haha. We are in the process of replacing 70's era handyman circuits and old knob and tube as well. As an example, there is 1 circuit that powers 4 upstairs rooms, a bathroom, hallway, attic commons, and 2 attic rooms. This is the lights and receptacles combined. Scary hazard, and it wouldn't help find anything. Thank god for low draw devices, CF/LED bulbs, and efficient flatscreens to put a mind more at ease. – dhaupin – 2016-04-15T15:27:04.703

No need to use WPS. Because it’s not available on all routers, all “true” WiFi repeaters can also be set up manually.

As per this document, it’s very easy:

Connect to your repeater via Ethernet (make sure WiFi isn’t connected)
Go to http://repeater.local/ and follow the instructions

On many WPS-capable routers, you can also “push” the WPS button in its web interface, so you don’t have to go crawling under your desk.

Daniel B

Posted 2016-04-10T09:45:23.827

Reputation: 40 502

Use a directional antenna. Sweep the house from at least 2 locations on opposite sides of the edge of the house. Use google maps and draw some lines or a cone where the signal is the loudest.

Then you'll have unsophisticatedly triangulated the router and have a far smaller area to search for it.

Directional antenna can be improvised with some foil and a plastic cup by surrounding a wireless card or a phone with a tinfoil-lined cup. Nowhere near as effective as a proper directional antenna, but it works.

Hydranix

Posted 2016-04-10T09:45:23.827

Reputation: 822

I've done this using a packet sniffer like tcpdump or Wireshark on a laptop. Put your Wi-Fi card in 802.11 Monitor Mode, tune it to the channel your AP (wireless router) is on, filter on your AP's MAC address as Address 2 (transmitter address) of the 802.11 header, and then watch the RSSI (signal strength) column of your sniffer. (If your sniffer doesn't display the RSSI column by default, you might need to tell it to show that column.)

Then walk around, watching the RSSI column, and play "warmer/colder" until you find where signal strength is highest. -40 is very warm, -30 is super hot.

Spiff

Posted 2016-04-10T09:45:23.827

Reputation: 84 656

thank you spiff. I will try that if the "easier" suggestion from gronostaj don't get me in front of the router. – SimonS – 2016-04-10T10:18:45.297

1I would recommend airodump-ng instead, it automates all the monitor mode setup. You can still start a packet capture program on the interface afterwards though for this situation it's not needed. – André Borie – 2016-04-10T15:16:07.860

Check the attic ;)

But really, you can attempt to trace the cable/phone line into the house, although that may not be accurate. Go in the basement and trace the cable/phone line, whichever it uses. You will see it shoot up through the floor, most likely just in front of a wall (on the baseboard). Check both floors, and then the attic. I found a router deep in an attic once with this tactic.....granted, it was 3 floors above the spot the wire shot up via the basement.

dhaupin

Posted 2016-04-10T09:45:23.827

Reputation: 343

If it's an ADSL router, it must be attached to a physical line somewhere. Find where the phone line comes into the house, and trace the phone lines from there. I assume the router is also plugged into a wall outlet and not battery-powered, but there are probably fewer phone outlets than electrical outlets in the house.

chepner

Posted 2016-04-10T09:45:23.827

Reputation: 5 645

Connecting a wireless device to the repeater

Plug the repeater into an outlet near the wireless router to configure it. Use a wireless device (for example a notebook, tablet, smartphone) to search for wireless networks in the vicinity.
Connect it to the wireless network Repeater [...]". Enter the wireless network (password)… You should search information about your repeater

user555689

Posted 2016-04-10T09:45:23.827

Reputation:

thank you for this suggestion, but to connect my repeater to the router, i need to click a button on the router itself and also on the repeater. so finding the router is a "must have" for this to work. Repeater & Router are from the same distributor, which is the ISP market leader in switzerland and they only offer this solution – SimonS – 2016-04-10T09:58:34.093

which brand is your repeater – None – 2016-04-10T09:59:40.690

swisscom, you won't know that one ;-) – SimonS – 2016-04-10T10:00:03.937

Read this – None – 2016-04-10T10:16:46.277

that's the instruction that came with the repeater. installing the repeater is not a problem at all. my problem is to find the router location. with the router I have, i need to push a button because i have an older model. – SimonS – 2016-04-10T10:17:47.000

While all the software and hardware tool mentioned are worth thinking about it is sometimes easier to just trace the cable that connects the router to the ISP's external network.

Requirements

Knowing with some certainty where the cable is at some point. An obvious place to look is where the cable enters the residence (works for satellite, too because you start at the dish).
The cable has to be sufficiently exposed to be traced. If the run is inside a duct, above a fixed ceiling, below a fixed floor and so on it may simply not be possible to follow.
You need to be able to access the the space where the cable runs easily enough to justify this. Mine runs through my crawl space which means hands and knees work on a dry gravel bed. I'm OK with that, but if it meant belly crawling in mud I'd try other things first. Runs in the attic where blow-in insulation has been added since the run was laid can be tough too (and come with the risk of missing your footing and stepping through the ceiling).

dmckee --- ex-moderator kitten

Posted 2016-04-10T09:45:23.827

Reputation: 7 311

DIY: If you have an external antenna, Use aluminum foil to degrade the signal as much as you can. Or shape it in a way where you only receive signal from a certain direction. Walk around monitor signal strength and you'll find it pretty quick, likely when you have a full bar you're probably standing on it. No software required, Only eyes. Good luck

NotAdmin Dave

Posted 2016-04-10T09:45:23.827

Reputation: 2 771