If I go to https://whatismyipaddress.com/ or similar, I get an IP address from the 194.11x.x.x range.

If I go to my ASP.NET MVC application from the same computer, it uses context.Connection.RemoteIpAddress in the middleware, and it gets a 10.x.x.x range. I land in the same range if I access my web site from my mobile, which is in the mobile network.

What happens here? I mean it should be some router or something, but why do IP detection sites get my IP right, but my ASP.NET host not?

CodePudding user response：

It is because you're trying to get the IP from your local machine. If you deploy the application it should display your IP instead of your local IP.

CodePudding user response：

For the reference, in case somebody stumbles upon this. On most websites you get code like context.Connection.RemoteIpAddress to get the client IP, including this middleware guide: https://docs.microsoft.com/en-us/aspnet/core/security/ip-safelist?view=aspnetcore-6.0

Everything works until you deploy to a hosting with reverse proxy (thank you @Llama), where in order to prevent DDoS attacks your request lands on a proxy that forwards your request to your website.

Most hostings would pass the original IP along though. You can get it like context.Request.Headers["X-Forwarded-For"].FirstOrDefault().