ASUS RT-AC88U forcing to assign a static ip address

[RMerlin]

See if you wouldn't have accidentally enabled the Windows Internet Connection Sharing on your PC, which would explain why the DHCP packets are coming from your Windows 10's MAC address. Or if you run any VM on it, check that the VM doesn't run any kind of DHCP server as well.

Next step would be to set your PC with a static IP within that rogue subnet (i.e. 192.168.0.100), then see if a web browser pointed at 192.168.0.1 might return any useful info.

 

[ColinTaylor]

https://answers.syr.edu/display/os/Disable+Internet+Connection+Sharing+in+Windows+10

Also, does to PC have 2 (or more) network adapters connected at the same time? Perhaps wired and wireless?

 

[Kwan]

See if you wouldn't have accidentally enabled the Windows Internet Connection Sharing on your PC, which would explain why the DHCP packets are coming from your Windows 10's MAC address. Or if you run any VM on it, check that the VM doesn't run any kind of DHCP server as well.

Next step would be to set your PC with a static IP within that rogue subnet (i.e. 192.168.0.100), then see if a web browser pointed at 192.168.0.1 might return any useful info.

Unfortunately that yielded no results I don't run any VMs, and Windows Int Connection Sharing wasn't on. Colin, thank you, but no, I'm only running wireless. There are other adaptors for VPN, ethernet service etc. but all disabled.

I've noticed I am having to re-connect to the wireless network now. Weirdness

 

[ColinTaylor]

Well there's definitely something attached to your network (a Samsung device?) with address 192.168.0.1 that's running a DHCP server.

An ISP supplied cable modem/router accidentally plugged into LAN port instead of WAN? (Yes, I'm clutching at straws here.) It might be time to start disconnecting things one at a time. Or try Merlin's suggestion:

Next step would be to set your PC with a static IP within that rogue subnet (i.e. 192.168.0.100), then see if a web browser pointed at 192.168.0.1 might return any useful info.

 

[RMerlin]

I saw something similar about a month ago. (RT-AC66U running 378.56_2). Although I reserved a specific IP address for a new client, the client did not seem to get this address, even when the lease was renewed.

So I deleted the reservation and then recreated it, this time using CAPITAL letters instead of small letters in the MAC address.

Afterwards it worked as expected.

I was pressed for time and just happy that it worked, so did not investigate whether the capital letters indeed solved the problem, or if it was just a coincidence.

Just to be safe, I've made the webui convert any user-entered MAC into uppercase on the DHCP reservation page. It shouldn't make a difference for dnsmasq, but it might prevent other issues related to the networkmap.

 

[Kwan]

Well there's definitely something attached to your network (a Samsung device?) with address 192.168.0.1 that's running a DHCP server.

An ISP supplied cable modem/router accidentally plugged into LAN port instead of WAN? (Yes, I'm clutching at straws here.) It might be time to start disconnecting things one at a time. Or try Merlin's suggestion:

The device (based on tracing the MAC address) is actually the Windows computer I'm running Wireshark on. Note it is sending to 255.255.255.255 so I'm wondering if 192.168.0.1 offering isn't normal and perhaps just some internal (as opposed to network) offering? I only have one router, and one TP Powerline setup - nothing else on my system "should" be routing traffic - if I had a router I knew of I'd be unplugging it in a second - reset the powerline just in case, but not change to Wireshark results.

 

[Kwan]

MYSTERY SOLVED!!!

First I'd like to extend my sincere thanks to everyone who helped out, RMerlin and Colin in particular.

I sent the snippet from Wireshark to my colleague in IT at work, and he pointed out that the bottom part of Wireshark indicates the bad offer was from a Samsung device. Didn't make sense - only Samsung device I had was a tablet. I was beginning to think I was running a DHCP Virus. But checked the MAC and it didn't agree. Didn't know of any other Samsung devices so I was puzzled.

So ... I then scanned through each of the MAC addresses stored in my router, and found - the WINK Hub? The home automation hub $%^$ was the issue and googling found the item mentioned on Reddit. Unplugged it for a while, re-plugged it, and the rogue DHCP offer has *whew* disappeared!

Again, thank you. Anyone with a Wink Hub may want to watch for DHCP issues.

 

[ColinTaylor]

@Kwan Thanks for the update. Glad you tracked it down. (The internet-of-things will be the death of us.)