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I have a DSL modem with WiFi, and on the list of devices connecting to it, there is one device that is foreign to me (10.163.55.254 in the screenshot below). How can I track down what it is and where it comes from?

enter image description here

What is this device? Can I track it? Can I identify it?

What I know:

  1. This DSL modem is a Thomson TG585v7 DSL modem/router with ISP-specific custom firmware, so I can't do much in terms of configuration, and the manufacturer manual has limited applicability. I've connected my own Linksys router to the DSL modem, and normally all my devices connect to the Linksys so the Thomson normally only "sees" the Linksys as sole client.
  2. My WiFi is WPA2 secured so I'm certain that the unknown doesn't have access to my network and data. I'm not concerned, just puzzled.
  3. The DSL modem (10.0.0.138) has two known LAN devices (.1 and .2) and two known WiFi devices (.3 and .4) - all on the correct subnet (255.255.255.0). There is no third "unknown" interface. The unknown device must connect via WiFi, but I don't understand why that isn't specified then.
  4. The unknown device is on the 255.0.0.0 subnet which is not in use. That can't possibly work.
  5. I can click into the details of the unknown device and delete it. It will reappear within a few minutes. There is no further information shown, other than that it is active and has the IP&MAC addresses I see. The chosen IP address is static of course, otherwise it would have received 10.0.0.5 by my DSL modem's DHCP service.
  6. The name of the unknown device includes its MAC address. I have checked all my devices (including the MAC addresses for WAN/LAN/WiFi for both the DSL router and the Linksys); it's not one of mine!
  7. I live in an apartment building. This device might belong to a neighbor. If so, the owner is clueless because he should at the very least notice that it doesn't have any connection. None of my neighbors even know what a MAC address is, so it would be pointless to ask, or put up a notice.
  8. Both the Thomson and the Linksys devices received factory resets by me today while I configured it again from scratch, so any weird old settings are certainly gone.

Update:
Moab proved to me that it's something within my own infrastructure. I know it's not anything I configured myself, and it's something that survives a factory reset. Perhaps it's a service interface added into the DSL modem's custom firmware by the ISP (tinfoil alert!) or whatever.

I'm satisfied knowing that whatever it is, it's not foreign. And it doesn't seem to disturb my network. I will move in half a year and ditch the DSL modem then. Let's see if it survives that! :-)

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1  
Do you have a switch? Do you have a separate 5GHz wifi network built into the router? These are two possibilities just off the top of my head. –  user3463 Aug 26 '12 at 18:23
    
+1 For @RandolphWest's suggestion. I seem to recall having a similar situation with a Thomson modem a few years back. That would imply it is something about the modem itself and not your specific network. –  terdon Aug 26 '12 at 18:26
    
I suspected that too but I checked all my devices including the MAC addresses for WAN/LAN/WiFi for both the DSL router and the Linksys and it's not one of them. I keep a log of my devices and I'm fairly certain I've never seen this MAC before; it's not mine. –  Torben Gundtofte-Bruun Aug 26 '12 at 18:35
    
Has this device only recently appeared? Any changes on your network? –  w3d Aug 26 '12 at 19:05

2 Answers 2

up vote 4 down vote accepted

Looks like something you created, see your own Question here, refer to member "irrational John" answer.

enter image description here

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Oh what a good find! I had completely forgotten that question. What is not evident though (because I regretfully neglected to follow up on it) is that I really didn't configure that IP address. But you've proven to me that, whatever it is, it's something within my infrastructure!! –  Torben Gundtofte-Bruun Aug 26 '12 at 20:50

The MAC of the unknown device is assigned as Alcatel/Lucent. If I were to guess it is most likely the router half of your combo device.

 8C-90-D3   (hex)       Alcatel Lucent
 8C90D3     (base 16)   Alcatel Lucent
                        600 March Drive
                        Ottawa ON K2K 2E6
                        CANADA

Your attention is called to the fact that the firms and numbers listed may not always be obvious in product implementation. Some manufacturers subcontract component manufacture and others include registered firms' OUIs in their products.

Source: IEEE OUI Lookup

share|improve this answer
    
Thanks. I don't have any devices from these vendors, but perhaps it's just the chipset within some device. I checked all my devices including the MAC addresses for WAN/LAN/WiFi for both the DSL router and the Linksys and it's not one of them. I keep a log of my devices and I'm fairly certain I've never seen this MAC before; it's not mine. –  Torben Gundtofte-Bruun Aug 26 '12 at 18:36
    
It may just be the bridge between the dsl modem and wifi –  Keltari Aug 26 '12 at 18:38

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