Web API - Blocking specific calls to the server

Then I managed to block the application in another way, through the I.P. Through some research I saw that this was the best solution to apply to the system, which is an Owin system.

Solution :

Follow the solution:

 public static string GetIP(this HttpRequestMessage request)
        {
            if (request.Properties.ContainsKey("MS_OwinContext"))
            {
                return HttpContext.Current != null ? HttpContext.Current.Request.GetOwinContext().Request.RemoteIpAddress : null;
            }
            if (request.Properties.ContainsKey("MS_HttpContext"))
            {
                return HttpContext.Current != null ? HttpContext.Current.Request.UserHostAddress : null;
            }
            return null;
        }

    public static bool AllowIP(this HttpRequestMessage request)
    {
        string whiteList= ConfigurationManager.AppSettings["whiteListIp"];
        if (!IsNullOrEmpty(whiteList))
        {
            string[] ipList = whiteList.Split(';');
            var ipAdress= request.GetIP();
            bool ipAllowed = ipList.Where(x => x.Trim().Equals(ipAdress, StringComparison.InvariantCultureIgnoreCase)).Any();
            return ipAllowed;
        }
        else return true;
    }

Filter:

    public class AllowedIpFilter: DelegatingHandler
        {
            protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, 
CancellationToken cancellationToken)
            {
                if (request.AllowIP())
                {
                    return await base.SendAsync(request, cancellationToken);
                }
                return request.CreateErrorResponse(HttpStatusCode.Unauthorized, "Access denied!");
        }
    }