ccna 200-301 gns3

ccna 200-301 gns3.Packet sniffers can only work in the same conflict domain as the network being attacked, unless the attacker is connected to an intermediate switch. There are many free software and shareware packet sniffers available on the web, such as Wiresharko1.3.1.4 ping scanning and port scanningWhen used as a legitimate tool, the ping scan and port scan application runs a series of tests on hosts and devices to identify services that are vulnerable to attack. Information is gathered by examining IP addresses and ports, banners, or data from TCP and UDP ports. Attackers use this information to compromise systems.Internet information queries can reveal information such as the holder of a particular domain, and the address assigned to that domain, as well as16 Chapter 1 Modern Network Security Office Breveal information such as the holder of a specific IP address and the domain associated with that address.A ping scan is a basic network scanning technique that determines which 1P address range maps to a surviving host. A single ping scan can indicate whether a particular host computer exists in the network. A ping scan contains ICMPecho request packets sent to multiple hosts. If a given address is active, that address will return an ICMP echo reply packet. A ping scan is an older and slower method used to scan a network.Each service on a host has a well-known port number associated with it. A port scan is a scan of a range of TCP or UDP port numbers on a host to detect listening services. It consists of sending a message to each port on the host. The response received by the sender indicates whether the port is being used.A ping scan of the addresses displayed by the Internet Information Query can present a list of active hosts in a given environment. Once such a list is generated, the port scanning tool can traverse all well-known ports to provide a complete list of all services running on the hosts found by the ping scan. The hacker then examines the characteristics of the active application, which can help the hacker find specific information to compromise that service.1.3.1.5 Mitigating Reconnaissance Attacks