neighborhood cable modem handing out DHCP

[icecream-guy]

Someone in my neighborhood has misconfigured a modem, that hands out DHCP address

we had a power failure this morning, and I keep getting IP addresses from this modem,  and I cannot access the internet.

it is a Netgear device

how can I get around this issue,  I do not know who in the neighborhood has the device.

[deanwebb]

I'd go with static IP that goes with your own network range, with DNS and default gateway configured.

It would take at least 2 receiving stations with the ability to measure signal strength to triangulate where the bad modem happens to be.

[Otanx]

Do you have your own cable modem, or do you share? It would be really weird for you to get leases from a neighbor unless there is a bridge between the networks besides the cable modem.

-Otanx

[deanwebb]

Do you have your own cable modem, or do you share? It would be really weird for you to get leases from a neighbor unless there is a bridge between the networks besides the cable modem.

-Otanx

Or if the neighbor really cranked up the gain on his wireless side.

[Otanx]

Or if the neighbor really cranked up the gain on his wireless side.

That would be a different SSID, and shouldn't cause issues unless you joined that network. If this is a shared SSID then like Dean said good luck triangulating the signal. The easier way would be to setup a system to keep requesting IPs with different MACs from their DHCP server untill you exhaust the configured pool.

-Otanx

[deanwebb]

Or if the neighbor really cranked up the gain on his wireless side.

That would be a different SSID, and shouldn't cause issues unless you joined that network. If this is a shared SSID then like Dean said good luck triangulating the signal. The easier way would be to setup a system to keep requesting IPs with different MACs from their DHCP server untill you exhaust the configured pool.

-Otanx

Such tools do exist, and you don't even have to speak Russian to use them!

[icecream-guy]

my firewall is wired to the network. my firewall is connected to modem is picking up IP address.  modem is connected to cable. cable is a shared medium, no wireless.

[Dieselboy]

I was also thinking like Otanx said but my post was not sent yesterday for some reason.

But also I am thinking along these lines: Cable = DOCSIS (COAX) at your premises? Like: COAX from the street -> DOCSIS modem -> your firewall. Can you check if the docsis modem is netgear?

[icecream-guy]

I was also thinking like Otanx said but my post was not sent yesterday for some reason.

But also I am thinking along these lines: Cable = DOCSIS (COAX) at your premises? Like: COAX from the street -> DOCSIS modem -> your firewall. Can you check if the docsis modem is netgear?

my modem is netgear, and the offending device is also netgear

Mine ( i pulled this from my modem GUI)
8C:3B:AD:DB:7D:28

offender
outside 192.168.100.1 2c30.33de.ad02

I guess that doesn't really prove anything, since the DOCSIS Modem does not have IP,  probably a wireless Netgear device on other side of remote modem handing out IP.  I can't really tell what DOCSIS Modem is on offender side.

[Dieselboy]

I think the offending device is your local docsis modem. Does it have a sticker on it that you can confirm the case? Like a name of manufacturer or mac address?

[icecream-guy]

I think the offending device is your local docsis modem. Does it have a sticker on it that you can confirm the case? Like a name of manufacturer or mac address?

NETGEAR CM1000
the modem is a pass throuhg device, there is not IP assigned

mac provided was not my modem, it was my AP.

[icecream-guy]

See private area for packet capture to protect my IP