CCNA – DHCP Explanation

Dynamic Host Configuration Protocol (DHCP) Explanation for your CCNA Exams reference…

DHCP Description:

  • DHCP works in a client/server mode. DHCP enables DHCP clients on an IP network to obtain their configurations from a DHCP server.
  • DHCP is not intended for configuring routers, switches, and servers. These type of hosts need to have static IP addresses.
  • DHCP works by providing a process for a server to allocate IP information to clients. Clients lease the information from the server for an administratively defined period. When the lease expires the client must ask for another address, although the client is typically reassigned the same address. Administrators typically prefer a network server to offer DHCP services because these solutions are scalable and relatively easy to manage. Cisco routers can use a Cisco IOS feature set, Easy IP, to offer an optional, full-featured DHCP server.
  • Administrators set up DHCP servers to assign addresses from predefined pools. DHCP servers can also offer other information, such as DNS server addresses, WINS server addresses, and domain names. Most DHCP servers also allow the administrator to define specifically what client MAC addresses can be serviced and automatically assign them the same IP address each time. DHCP uses User Datagram Protocol (UDP) as its transport protocol. The client sends messages to the server on port 67. The server sends messages to the client on port 68.

CCNA Exam 642-586 – Advanced Wireless LAN for System Engineers

CCNA Exam 642-586
Title: Advanced Wireless LAN for System Engineers
Ver: 02.07.07

Example Question out of 70 Questions:

Certkiller .com is adding a new branch office with 60 access points and 120 users that requires WDS to support a wireless VoIP application on a single subnet. Additionally, the customer requires local authentication services to provide authentication capability in the event of a WAN failure. Which product will support the customer requirements?
A. Cisco 2811 Integrated Services Router
B. Cisco 3745 Multiservice Access Router
C. Cisco 3845 Integrated Services Router
D. Cisco 2851 Integrated Services Router

CCNA Exam 642-551 Securing Cisco Network Devices

CCNA Exam 642-551
Title: Securing Cisco Network Devices
Ver: 02.28.07

Example Question out of 62 Questions:

What is a reconnaissance attack?
A. when an intruder attacks networks or systems to retrieve data, gain access, or escalate access privileges.
B. when an intruder attempts to discover and map systems, services, and vulnerabilities
C. when malicious software is inserted onto a host in order to damage a system, corrupt a system, replicate itself, or deny service or access to networks, systems, or services
D. when an intruder attacks your network in a way that damages or corrupts your computer system, or denies you and other access to your networks, systems, or services
E. when an intruder attempts to learn user IDs and passwords that can later be used in identity theft

Answer: B
Explanation: Attackers and hackers can employ social engineering techniques to pose as legitimate people seeking out information.