Weird problem with IP address

[Swampthing]

I have one computer I hadn't been using for awhile, recently powered it up to convert it to an arcade cabinet machine. For some weird reason this computer is pulling the IP address straight from my ISP even though it's plugged in to the same router every other machine is plugged into. This machine is pulling a 66.X.X.X address instead of the 192.168.X.X address it should be pulling. I've tried manually assigning an IP but when I do that it's not able to access the internet or network at all.

I've tried disabling and re-enabling the adaptor, multiple ports on the router and nothing i do is able to get a local IP assigned instead of the one direct from the ISP.

Anyone seen this before or have any thoughts?

 

[VirtualLarry]

I would double-check your LAN versus WAN connections on the router in question. After that, I would check VLAN settings. After that, I would posit that the switch in the router, may be defective (or the entire router).

One nasty trick that can be used to abuse consumer-grade routers, is to overload the ports with packets, crashing the router, and some routers, the switch is used for both the LAN and WAN ports, and without proper software control, all of the ports get bridged, leaking WAN directly into LAN and vice-versa, which can then be used to attack machines, since effectively the NAT/SPI firewall is entirely bypassed by a switch vulnerability.

This was more common back in the WRT54GL-ish days, but not entirely unheard of in modern routers too.

This can also happen, when routers "get old".

 

[JackMDS]

What would happen if you disconnected the WAN port and keep it open for few minutes?

 

[ericlp]

do an ipconfig /all on your machine to verify you only got one IPV4 and it going to the right hardware port. Sometimes you can get some virtualbox crap loaded on the machine...

Do a snapshot of your ipconfig and post it up here.

 

[Genx87]

This machine maybe put into the DMZ or NAT out to the internet by chance? To me it seems like its physical interface is being presented on the WAN to the ISP.