Non private address in lan

Question

What is a potential problem of using non private addresses in lan? Such as one over an image. This is a open wi-fi connection of a hotel. Internet works. Why then rfc1918 needs at least?

Answer 1

Illegal Addresses

Private intranets that have no intent on connecting to the Internet can choose any addresses they want, even public addresses that have been assigned by the InterNIC. If an organization later decides to connect to the Internet, its current address scheme might include addresses already assigned by the InterNIC to other organizations. These addresses would be duplicate or conflicting addresses and are known asillegal addresses . Connectivity from illegal addresses to Internet locations is not possible.

For example, a private organization chooses to use 207.46.130.0/24 as its intranet address space. The public address 207.46.130.0/24 has been assigned to the Microsoft corporation and routes exist on the Internet routers to route all packets destined to IP addresses on 207.46.130.0/24 to Microsoft routers. As long as the private organization does not connect to the Internet, there is no problem because the two address spaces are on separate IP internetworks. If the private organization then connected directly to the Internet and continued to use 207.46.130.0/24 as its address space, then any Internet response traffic to locations on the 207.46.130.0/24 network would be routed to Microsoft routers, not to the routers of the private organization.

Solution