The Cisco router will respond with certain keywords, identifying itself when connection attempts are made to some ports. By knowing what these keywords are, a hacker can determine what type of network device the node is. When connecting to ports 23 or 2001, the typical response is as illustrated.
If a Web browser is used to connect to ports 2001, 4001 and 6001, the router returns a Cisco-specific response of "bad passwords."
The "finger" utility can also return information identifying the router. |