How to get the public IP address of the user if the server is behind the router?

Question

How can I get the public IP address of a user if my server is behind a router?

I'm trying to:

protected string GetIPAddress() { System.Web.HttpContext context = System.Web.HttpContext.Current; string ipAddress = context.Request.ServerVariables["HTTP_X_FORWARDED_FOR"]; if (!string.IsNullOrEmpty(ipAddress)) { string[] addresses = ipAddress.Split(','); if (addresses.Length != 0) { return addresses[0]; } } return context.Request.ServerVariables["REMOTE_ADDR"]; } 

but all i get is a router gateway.

Apparently REMOTE_ADDR will not work in my case, and there will be no HTTP_X_FORWARDED_FOR .

Any ideas on how to get the user's public IP address in my case?

Thanks.

Answer 1

There is no way to get it.

But you can find out if the user opens the page from the local network or from the Internet.

If the IP is the IP address that the router assigns to requests coming from the Internet, it clears it from the network.

Answer 2

You are trying to deal with IP and HTTP routing.

At the application level, the packet has already passed the Routing / IP level, and this information has been deleted.

The packet that you see at the HTTP level is likewise sent by the remote endpoint at the application level , which is devoid of IP address information, so a search in the HTTP headers won't help IMHO.

EDIT: As @Marc Gravell said, some reverse proxies add this information to the HTTP headers. So you should check yours (if you have it configured) if it does.

This answer lists some other server variables that you could check.

Answer 3

The only reliable way is to turn to a well-known service on the Internet that will tell you which IP address your request sees. Of course, this service must continue to function and be available or this function breaks down. For example, http://whatismyip.com