router plugged in backwards, ISP protocol issue.
Good Morning/Day all!
I’m working towards getting my CySa cert and been brushing up on the networking side of things. There was this particularly odd behavior at a small Wireless ISP I worked for. I’m trying to find out what protocol would prevent the following scenario that would sometimes occur at a very small Wireless ISP I worked for in the early 2000’s.
I worked for a small wireless ISP that offered direct line of site connections, users would bring their own routers. Some, well a lot of people then would just have 1 PC connected via Ethernet, no routers. We would get a call from a customer that they were down, no internet, …check the obvious, Do you have a router? No. IP Config … well you are pulling a 192.168.x.x. I would end up having them arp -a, find the offending MAC, search for the MAC via the CLI for that tower, and find the offending radio/customer. I would shut the offending customer’s radio off, call them and instruct to correct the way they have their router connected, advised they have it plugged in backwards. They would have the radio plugged in into one of the ports 1 – 4, and not the internet/WAN port, aka the yellow port. This would in return, after having the calling customer do a IP reset, would then get a WAN IP and have internet.
My question is, what protocol prevents that scenario from happening in the first place?
Can anyone help?