Are you doing this in a Controller or a View?

In my views, I have access to Context automatically, which is nice.

In a controller, you have to do a few steps:

1. Add a private field to hold your context: private readonly IHttpContextAccessor _httpContext;

2. Add IHttpContextAccessor httpContextAccessor to your constructor ... , IHttpContextAccessor httpContextAccessor) : base(logger, compositeViewEngine, umbracoContextAccessor)

3. set your private field: _httpContext = httpContextAccessor;

4. Use it your controller :-) _httpContext.HttpContext.Request...

So this a more a .net core thing than an umbraco thing.

Here is a controller example:

public class ContentFolderController : RenderController
{
    private readonly IHttpContextAccessor _httpContext;

    public ContentFolderController(ILogger<ContentFolderController> logger,
        ICompositeViewEngine compositeViewEngine,
        IUmbracoContextAccessor umbracoContextAccessor,
        IHttpContextAccessor httpContextAccessor)
        : base(logger, compositeViewEngine, umbracoContextAccessor)
    {
        _httpContext = httpContextAccessor;
    }

    public override IActionResult Index()
    {
        //use context to get ip
        var userIp = _httpContext.HttpContext.Connection.RemoteIpAddress;


        return View("~/Views/SmartContentFolder.cshtml", CurrentPage);
    }
}