Well, technically it's not an error, precisely it's something that I recently had to investigate at work and the solution was that, create a VIP (Virtual IP) to which also responds to requests.
This can be done in both windows and linux and indeed it can be useful in certain scenarios.
In my case, I had a gateway problem that I solved this way, let's take the example, 3 devices, A, B and C connected like this.
A -- B -- C
A and C can't see or route each other since they have different gateways and their network configuration can't be modified, so B has 2 IP's on each of its interfaces, let's say they are X.10 and X.20. When A communicates with B through X.10, the real recipient of the packet is B. When it does so through X.20, B takes those packets, and does an IPTABLES to C, in this way A thinks it's communicating with B but in reality it's communicating with C through this second IP that B has. And the same between B and C.
I don't know if I've been understood.... it's something strange if haha.
On the other hand, if you have a windows where you're changing IP's constantly, you can go to the adapter properties and put there several IP's that you want the computer to respond to, in this way, when changing networks you don't have to go modifying the IP's at each moment.
They are rare cases but in which it can be useful.
Regards.

