直接上代碼：
public class DosAttackModule : IHttpModule
{
void IHttpModule.Dispose() { }
void IHttpModule.Init(HttpApplication context)
{
context.BeginRequest += new EventHandler(context_BeginRequest);
}
private static Dictionary<string, short> _IpAdresses = new Dictionary<string, short>();
private static Stack<string> _Banned = new Stack<string>();
private static Timer _Timer = CreateTimer();
private static Timer _BannedTimer = CreateBanningTimer();
private const int BANNED_REQUESTS = 1; //規定時間内通路的最大次數
private const int REDUCTION_INTERVAL = 1000; // 1 秒（檢查通路次數的時間段）
private const int RELEASE_INTERVAL = 5 * 60 * 1000; // 5 分鐘（清除一個禁止IP的時間段）
private void context_BeginRequest(object sender, EventArgs e)
{
string ip = HttpContext.Current.Request.UserHostAddress;
if (_Banned.Contains(ip))
{
HttpContext.Current.Response.StatusCode = 403;
HttpContext.Current.Response.End();
}
CheckIpAddress(ip);
}
/// <summary>
/// 檢查通路IP
/// </summary>
private static void CheckIpAddress(string ip)
{
if (!_IpAdresses.ContainsKey(ip)) //如果沒有目前通路IP的記錄就将通路次數設為1
{
_IpAdresses[ip] = 1;
}
else if (_IpAdresses[ip] == BANNED_REQUESTS) //如果目前IP通路次數等于規定時間段的最大通路次數就拉于“黑名單”
{
_Banned.Push(ip);
_IpAdresses.Remove(ip);
}
else //正常通路就加次數 1
{
_IpAdresses[ip]++;
}
}
#region Timers
/// <summary>
/// 建立計時器，從_IpAddress減去一個請求。
/// </summary>
private static Timer CreateTimer()
{
Timer timer = GetTimer(REDUCTION_INTERVAL);
timer.Elapsed += new ElapsedEventHandler(TimerElapsed);
return timer;
}
/// <summary>
/// 建立定時器，消除一個禁止的IP位址
/// </summary>
/// <returns></returns>
private static Timer CreateBanningTimer()
{
Timer timer = GetTimer(RELEASE_INTERVAL);
timer.Elapsed += delegate { _Banned.Pop(); }; //消除一個禁止IP
return timer;
}
/// <summary>
/// 建立一個時間器，并啟動它
/// </summary>
/// <param name="interval">以毫秒為機關的時間間隔</param>
private static Timer GetTimer(int interval)
{
Timer timer = new Timer();
timer.Interval = interval;
timer.Start();
return timer;
}
/// <summary>
/// 減去從集合中的每個IP位址的請求
/// </summary>
private static void TimerElapsed(object sender, ElapsedEventArgs e)
{
foreach (string key in _IpAdresses.Keys)
{
_IpAdresses[key]--;
if (_IpAdresses[key] == 0)
_IpAdresses.Remove(key);
}
}
#endregion
}
這個前提是用戶端沒有使用動态代理IP。。 轉載于:https://www.cnblogs.com/m4LWJ/archive/2013/04/12/3016465.html