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How to find WAP which has DHCP disabled behind switch?

Discussion in 'Networks & Internet Connectivity' started by Gimpymoo, May 11, 2019.

  1. Gimpymoo

    Capodecina

    Joined: May 31, 2005

    Posts: 14,660

    Location: Nottingham

    I have a router configured as a WAP which is behind a switch.

    I have forgotten the IP address of the router and need to change the wifi key but owing to the config and to save faff, wish to avoid factory resetting it.

    Any ideas as to how to find it as even though it has an IP, it if course is not broadcasting it.

    I hope that makes sense.

    Many thanks.
     
  2. SupraWez

    Wise Guy

    Joined: Nov 17, 2007

    Posts: 2,022

    Use a subnet scanner.

    If you can connect via wifi you should be able to see AP details from a device.
     
  3. pepp77

    Mobster

    Joined: Oct 13, 2008

    Posts: 3,466

    Location: SE London Born and Bred

  4. Gimpymoo

    Capodecina

    Joined: May 31, 2005

    Posts: 14,660

    Location: Nottingham

    It just gives the details of the router/firewall, as though the WAP is not actually there :D

    That is how I set it up though many moons ago so it is working.. I just forgot the IP AND the Wifi password so stumped myself.

    Many thanks.

    Giving it a go now.
     
  5. Steveocee

    Mobster

    Joined: Nov 5, 2011

    Posts: 4,350

    Location: Derbyshire

    Check the ARP cache of the router? May get lucky.
    I take it you static ip'd it rather than letting it be DHCP client otherwise that could work checking DHCP leases.

    Our add others have suggested a ping sweep.
     
  6. K.C. Leblanc

    Sgarrista

    Joined: Sep 13, 2003

    Posts: 7,997

    Location: Glocestershire

    I can't remember exactly how to do it but if you know the Mac address I believe that it's possible to effectively assign it an IP address by making a manual entry in the ARP cache on your computer. If you open a command prompt and enter ARP /? it should tell you how to make an entry.
     
  7. Gimpymoo

    Capodecina

    Joined: May 31, 2005

    Posts: 14,660

    Location: Nottingham

    Thanks, I will try that later.

    If I connect directly via ethernet and run a subnet scan, is it likely to find anything?

    Right now, it is acting as a pass through and is "invisible" to the network seeing as the router handles the IP assignment for the devices connected to the WAP if that makes sense?

    Checked ARP cache on the router, and not there either :(

    Determined not to reset out of principle now :D
     
  8. fezster

    Gangster

    Joined: Jan 7, 2007

    Posts: 427

    Subnet scanner as said.

    Then if there's a lot of potential results (unlikely on a home network), then use a port scanner to check the results to see which has port 80 open (assuming the default port has not been changed for the Web ui. Could be 443 if it uses https). This should narrow it down and you can then try through a Web browser.
     
  9. Steveocee

    Mobster

    Joined: Nov 5, 2011

    Posts: 4,350

    Location: Derbyshire

    If you connect directly you could use wire shark and see if it's shouting out
     
  10. bledd

    Don

    Joined: Oct 21, 2002

    Posts: 46,115

    Location: Parts Unknown

  11. Gimpymoo

    Capodecina

    Joined: May 31, 2005

    Posts: 14,660

    Location: Nottingham

    To update and summarise.

    Firstly, thanks to all who responded.

    I tried EVERYTHING advised and more and for some reason, I could get get a whiff from the thing on the network, even when connected directly to a PC, wirehsark or the scanners would not pick it up.

    I even connected a device to the router via wifi but when sniffing, the router acting as a WAP was completely transparent (Which is to be fair, what is should be doing).

    In the end, the router was old and the wifi protocols were outdated and as luck would have it, I found an old Virgin Superhub 2 lying around so re-purposed that as a WAP and all good.

    Just seems like it was the "perfect storm" of disabling DHCP and custom gateway address and your screwed on this specific router which by the way was a Netgear WNR2000.