Can a web user in US have Japanese IP?

I'm currently implementing a IP-to-country feature for a client in the US. The problem is开发者_如何学Python that when he does some tests by using machines in the US, some of the incoming IPs to his website are identified as Japanese IPs. My log file shows that those IPs start with 150.x.x.x and belongs to JAPAN NETWORK INFORMATION CENTER. He guarantees that when he checked IPs of those machines, they were shown as from the US.

More information: I use request.UserHostAddress (C#) to retrieve client's IP.

So my question is: what is the possible network configuration which can cause this issue?

Thank you in advance.

Edit: How about the situation in which a US user is using internet service of a Japanese company in the US?

He guarantees that when he checked IPs of those machines, they were shown as from the US.

Please ask where did he see that information, i.e. how did he geolocated.

I use request.UserHostAddress (C#) to retrieve client's IP

Well, this is the public IP. This can be the IP of the last peer. May be a proxy, a VPN router, (remote) office gateway.

Two most commonly used ways to have IP from different country: 1. Proxy 2. VPN

That field 'returns the fully qualified name of the client or the last proxy that sent the request'. The client's proxy chain might include a host in JP, or they might subscribe to a Japanese ISP.

Geolocation is not exact. There are errors in various Geolocation databases, and IP's can change (that is, they can be reassigned between different registries). So information can be out of date.

The problem is that way u only get the name of the client or the last proxy that sent the request.. a request can have many hops from client to server.