| 1.2 |  | Vulnerabilities and Threats |
| 1.2.3 |  | Reconnaissance |

| Reconnaissance is the unauthorized discovery and mapping of systems, services, or vulnerabilities. It is also known as information gathering and, in most cases, it precedes an actual access or Denial of Service (DoS) attack. The malicious intruder typically ping sweeps the target network to determine which IP addresses are alive. After this, the intruder uses a port scanner to determine what network services or ports are active on the live IP addresses. From this information, the intruder queries the ports to determine the application type and version, as well as the type and version of operating system running on the target host. Based on this information, the intruder can determine if a possible vulnerability exists that can be exploited. Reconnaissance is somewhat analogous to a thief casing a neighborhood for vulnerable homes to break into, such as an unoccupied residence, easy-to-open doors, or open windows .

Using, for example, the nslookup and whois utilities, an attacker can easily determine the IP address space assigned to a given corporation or entity . The ping command tells the attacker what IP addresses are alive.

| Web Links Explanation and Usage of TCP/IP Utilities http://www.microsoft.com/TechNet/ winnt/reskit/sur_util.asp Nslookup Online Tools
http://www.allwhois.com
http://cc-www.uia.ac.be/ds/nslookup.html
http://www.trulan.com/nslookup.htm

Whois Online Tools
http://www.whois.net

Combined Online Tools
http://centralops.net/co/
http://www.dslreports.com/tools
http://www.netcraft.com/
http://www.infosyssec.org/
infosyssec/tools2.htm