Computer Basics

Let’s test your knowledge of UDP, TCP, smurf attacks, EIGRP, and more with these questions designed to help you prepare for success on your CCENT, CCNA, CCNP, Network+, and Security+ certification exams! CCENT Certification / Network+ Certification: Which of the following protocols runs on both UDP and TCP? A. DHCP B. SNMP C. DNS D. ARP E. Inverse ARP Answer: C. DNS runs on port 53, both on TCP and UDP. Security+ Certification: Briefly define the term "smurf attack". (Not too briefly, though!) Answer: Basically, a smurf attack involves sends ICMP Echo packets (pings) with the intended victim's IP address specified as the source of the Echo packets. This transmission takes the form of a directed broadcast, which means that quite a few hosts can receive it - and then respond with ICMP Echo Replies, which will all be sent to the intended victim. CCNA Exam: R1 and R3 are directly connected at their respective Serial1 interfaces via a DTE/DCE cable. What command will tell you whether the interface is connected to the DTE or DCE end of the cable? Answer: Run show controller serial 1 on either router - the DTE / DCE information is near the top of the output. CCNP Certification / BSCI Exam: DUAL has discovered four possible paths to a remote network, with the following metrics: PathA, 1500. PathB, 1500. PathC, 2600. PathD, 3100. What command will allow EIGRP to use the first three paths without using the fourth? Answer: variance 2 would do the job. Any path with a metric of 3000 or lower will be utilized; setting it to 3 would bring PathD into the equation. CCNP Certification / BCMSN Exam: What is the main purpose of IEEE 802.3ac? Answer: The IEEE 802.3ac standard allows the maximum frame length to be extended to 1522 bytes, which means the dot1q 4-byte header doesn't cause problems in transmission. CCNP Certification / ONT Exam: Which queueing strategy gives priority to interactive, low-bandwidth communications by default? Answer: Weighted Fair Queueing (WFQ) gives priority to interactive, low-bandwidth conversations, and then splits the remaining bandwidth fairly among the remaining conversations. Look for a new set of Cisco and CompTIA certification exam questions soon!