使用HttpModules 来限制IP地址的访问

///

/// HTTP module to restrict access by IP address
///

public class SecurityHttpModule : IHttpModule
{
public SecurityHttpModule() { }

    public void Init(HttpApplication context)
    {
        context.BeginRequest += new EventHandler(Application_BeginRequest);
    }

    private void Application_BeginRequest(object source, EventArgs e)
    {
        HttpContext context = ((HttpApplication)source).Context;
        string ipAddress = context.Request.UserHostAddress;
        if (!IsValidIpAddress(ipAddress))
        {
            context.Response.StatusCode = 403;  // (Forbidden)
        }
    }

    private bool IsValidIpAddress(string ipAddress)
    {
        return (ipAddress == "127.0.0.1");
    }

    public void Dispose() { /* clean up */ }
}