Detecting DoS / DDoS Attack on a Windows 2003 / 2008 Server




Question: How do I detect a DDOS (Distributed denial of service) / DOS attack on a Windows Server 2003 / 2000 / 2008? Can I use Linux netstat command syntax to detect DDoS attacks?

Answer:A denial-of-service attack (DoS attack) or distributed denial-of-service attack (DDoS attack) is an attempt to make a computer resource unavailable to its intended users.

You can always use netstat command to get list of connections under Windows. Open command prompt by visiting Start > Run > Type "cmd" in box.

netstat is a command line utility which displays protocol statistics and current TCP/IP network connections in a system. Type the following command to see all connections:
netstat -noa

 n: Displays active TCP connections, however, addresses and port numbers are expressed numerically and no attempt is made to determine names.

o: Displays active TCP connections and includes the process ID (PID) for each connection. You can find the application based on the PID on the Processes tab in Windows Task Manager.

 a: Displays all active TCP connections and the TCP and UDP ports on which the computer is listening.

You can use find command as filter to searches for a specific string of text in a file. In the following example you are filtering out port 80 traffic:
netstat -ano | find /c "80"
Find the IP address which is having maximum number of connection and block it using Cisco firewall or IPSec. Another protective measurement is to harden the TCP/IP stack.