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

Question

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".

Answer 1

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.

Answer 2

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.

Answer 3

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:

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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:

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My first ideas were to:

1. 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.

2. 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.

Answer 4

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.

Answer 5

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.

Answer 6

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:

1. Connect to your repeater via Ethernet (make sure WiFi isn’t connected)
2. 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.

Answer 7

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.

Answer 8

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.

Answer 9

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.

Answer 10

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.

Answer 11

Connecting a wireless device to the repeater

1. 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.
2. Connect it to the wireless network Repeater [...]". Enter the wireless network (password)… You should search information about your repeater

Answer 12

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).

Answer 13

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