312-38 Online Practice Questions and Answers

Correct Answer: C

Correct Answer: B

In serial data transmission, one bit is sent after another (bit-serial) on a single transmission line. It is the simplest method of transmitting digital information from one point to another. This transmission is suitable for providing communication between two participants as well as for multiple participants. It is used for all long-haul communication and provides high data rates. It is also inexpensive and beneficial in transferring data over long distances. Answer option D is incorrect. In parallel data transmission, several data signals are sent simultaneously over several parallel channels. Parallel data transmission is faster than serial data transmission. It is used primarily for transferring data between devices at the same site. For instance, communication between a computer and printer is most often parallel, allowing the entire byte to be transferred in one operation. Answer option A is incorrect. The unicast transmission method is used to establish communication between a single host and a single receiver. Packets sent to a unicast address are delivered to the interface recognized by that IP address, as shown in the following figure:

Answer option C is incorrect. The multicast transmission method is used to establish communication between a single host and multiple receivers. Packets are sent to all interfaces recognized by that IP address, as shown in the figure below:

Correct Answer: A

A stateful firewall is a firewall that keeps track of the state of network connections (such as TCP streams, UDP communication) traveling across it. The firewall is programmed to distinguish legitimate packets for different types of connections.

Only packets matching a known connection state will be allowed by the firewall; others will be rejected. Answer option B is incorrect. A stateless packet filter firewall allows direct connections from the external network to hosts on the internal

network and is included with router configuration software or with Open Source operating systems.

Answer option C is incorrect. It applies security mechanisms when a TCP or UDP connection is established.

Answer option D is incorrect. An application gateway firewall applies security mechanisms to specific applications, such as FTP and Telnet servers.

Correct Answer: BC

E-mail spam, also known as unsolicited bulk email (UBE), junk mail, or unsolicited commercial email (UCE), is the practice of sending unwanted e-mail messages, frequently with commercial content, in large quantities to an indiscriminate set of recipients. Answer option A is incorrect. Email spoofing is a fraudulent email activity in which the sender address and other parts of the email header are altered to appear as though the email originated from a different source. Email spoofing is a technique commonly used in spam and phishing emails to hide the origin of the email message. By changing certain properties of the email, such as the From, Return-Path and Reply-To fields (which can be found in the message header), ill-intentioned users can make the email appear to be from someone other than the actual sender. The result is that, although the email appears to come from the address indicated in the From field (found in the email headers), it actually comes from another source. Answer option D is incorrect. Email jamming is the use of sensitive words in e-mails to jam the authorities that listen in on them by providing a form of a red herring and an intentional annoyance. In this attack, an attacker deliberately includes "sensitive" words and phrases in otherwise innocuous emails to ensure that these are picked up by the monitoring systems. As a result, the senders of these emails will eventually be added to a "harmless" list and their emails will be no longer intercepted, hence it will allow them to regain some privacy.

Correct Answer: A

Correct Answer: A

Correct Answer: A

Correct Answer: Email tracking

Email tracking is a method for monitoring the e-mail delivery to the intended recipient. Most tracking technologies utilize some form of digitally time-stamped record to reveal the exact time and date at which e-mail was received or opened, as well the IP address of the recipient. When a user uses such tools to send an e-mail, forward an e-mail, reply to an e-mail, or modify an e-mail, the resulting actions and tracks of the original e-mail are logged. The sender is notified of all actions performed on the tracked e-mail by an automatically generated e-mail. eMailTracker Pro and MailTracking.com are the tools that can be used to perform email tracking.