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I have Verizon FiOS with an Actiontec MI424WR router. The system has been in place for a number of years with a couple dozen devices connected via wireless, hardwire, and coax (using MOCA to connect to a switch in another building).

The router's address is 192.168.1.1, and its DHCP address range is 192.168.1.2 through 254.

The other day, one of the devices, a Chromebox reported that it was connected to the network, but couldn't access the internet (whether wireless or hardwired). It was set to automatically configure, and I noticed that it had been assigned an IP address of 192.168.10.100, and that the gateway was 192.168.10.1. As noted above, this is not the range to which the router is set. All was fine when I manually entered an IP address within the proper range.

Since the other network devices seemed to work, I assumed the problem was with the Chromebox, so I factory-reset it. That did not solve the problem. I then installed a brand new network device, and discovered that it, too, received the wrong IP address.

This morning, I replaced the router. To my surprise, the problem persists. I now have three network devices that receive the wrong IP address and gateway IP. On two of them, I set the IP address manually. But the third device is a Nexus 5 running Android Marshmallow. It apparently has a bug that doesn't let me set a static address.

Any ideas about why the router is either providing the wrong address, or why some devices are misinterpreting?

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    Check what dhcp server gave the ip, and connect to it. ChromeCast stuff usually create a self wifi to allow you to configure it, and after it connect to your wifi. I guess it's something like that, that happen to you. – yagmoth555 Nov 13 '15 at 2:12
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It's very unlikely that your router is giving out wrong IP addresses.

The more likely cause is a rogue DHCP server on the network.

Tools are available that you can run on your workstation that will send out DHCP requests and tell you what replies you get (DHCP Find is one that I've used in the past). With that information, you'll be able to see what IP the DHCP replies are coming from as well as the culprit MAC address.

Once you have the MAC address, it's merely a matter of going through your switch CAM tables to find what port it's plugged into.

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  • Thank you for your reply. I only have two other wireless access points on the network, and both have their DHCP functions turned off. I did notice something else. When I run a subnet scan intentionally outside my range of 192.168.1.1 to 254, let's say to 195.168.1.254, I see devices outside of my location (e.g., 193.104.1.78 static.office-vienna.at). I'm assuming I should not be seeing these devices. I reported it to Verizon, and they said it was not a problem. Would I be wrong in assuming that some remote device's DHCP could be the culprit and that this could be a Verizon problem? – Alan M. Nov 13 '15 at 3:07
  • Well, if your router is permitting DHCP from outside your network, you have big problems. – EEAA Nov 13 '15 at 3:07
  • Thank you. I was pretty sure it shouldn't be that way but, like I said, Verizon didn't agree. That would explain why the problem suddenly cropped up. Thanks again. Voting for your answer now. – Alan M. Nov 13 '15 at 3:09
  • Wait, you scanned outside your LAN subnet and saw other devices outside of your subnet. Why is that surprising to you? – EEAA Nov 13 '15 at 3:10
  • It's a home network, and I assumed I shouldn't see outside the subnet because, up until this week, I never had before. – Alan M. Nov 13 '15 at 3:12

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