Basic Networking and Communications

Which layer of the OSI Model defines cable standards? A. Physical layer B. Data Link layer C. Network layer D. Transport layer

A. Cable standards are defined at the Physical layer, layer 1. They are not defined at the Data Link layer (layer 2), the Network layer (layer 3), or the Transport layer (layer 4).

You are purchasing a product from a website. Which of the following protocols will your system most likely use to provide confidentiality for this transaction? A. SSL B. SSH C. IPsec D. HTTP

A. E-commerce transactions use HyperText Transfer Protocol Secure (HTTPS) for confidentiality, and Secure Sockets Layer (SSL) is one of the protocols used to encrypt HTTPS. While not one of the choices, Transport Layer Security (TLS) is also commonly used to encrypt HTTPS. While Secure Shell (SSH) and Internet Protocol security (IPsec) both provide confidentiality with encryption, HTTPS doesn't use SSH or IPsec. HTTP sends data in cleartext, so it doesn't provide confidentiality.

What protocol would a system use to determine a system's physical address? A. ARP B. RARP C. BootP D. DNS

A. Systems use the Address Resolution Protocol (ARP) to identify the assigned physical (or MAC) address matching an assigned IP address. Reverse ARP (RARP) allows a system with a MAC address to get an IP address. The Bootstrap Protocol (BootP) allows a diskless system to get an IP address and then download the image of an operating system. Domain Name System (DNS) resolves host names to IP addresses but not physical addresses.

Which layer of the OSI Model includes TCP and UDP? A. Transport layer B. Network layer C. Data Link layer D. Application layer

A. The Transport layer includes the TCP and UDP protocols. These protocols are not implemented on the Network layer, the Data Link layer, or the Application layer.

Which of the following accurately identifies a difference between FTP and TFTP? A. FTP uses UDP, and TFTP uses TCP. B. FTP supports authentication, but TFTP does not support authentication. C. TFTP sends data across a network in cleartext, but FTP encrypts data. D. TFTP is primarily used to transfer large files, and FTP is used to transfer configuration information to and from network devices.

B. File Transfer Protocol (FTP) supports authentication, but Trivial FTP (TFTP) does not support authentication. FTP uses TCP ports 20 and 21, while TFTP uses UDP port 69. Both FTP and TFTP send data across a network in cleartext, but it is possible to encrypt FTP with Secure Shell (as SFTP). TFTP is commonly used to transfer configuration files to and from network devices, and FTP is primarily used to transfer large files.

Which of the following topologies avoids collisions using a token? A. IEEE 802.3 B. IEEE 802.5 C. CSMA/CD D. CSMA/CA

B. IEEE 802.5 defines token ring networks, which avoid collisions using a token. Ethernet (IEEE 802.3) attempts to detect collisions using Carrier Sense Multiple Access with Collision Detection (CSMA/CD). Wireless networks (802.11) attempt to avoid collisions using Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA).

Which of the following statements is correct related to IPsec? A. IPsec provides confidentiality by encrypting data with AH. B. IPsec provides confidentiality by encrypting data on the Network layer. C. IPsec AH uses protocol number 50. D. IPsec ESP uses protocol number 51.

B. Internet Protocol security (IPsec) provides confidentiality by encrypting data on the Network layer. Encapsulating Security Payload (ESP) provides confidentiality by encrypting data, but Authentication Header (AH) only provides authentication and integrity. AH uses protocol number 51, and ESP uses protocol number 50.

What port does POP3 use? A. 25 B. 110 C. 143 D. 443

B. Post Office Protocol version 3 (POP3) uses TCP port 110. Simple Mail Transfer Protocol (SMTP) uses TCP port 25. Internet Message Access Protocol version 4 (IMAP4) uses TCP port 143. HyperText Transfer Protocol Secure (HTTPS) uses TCP port 443.

Which layer of the OSI Model packages data as a frame? A. Physical layer B. Data Link layer C. Network layer D. Transport layer

B. The Data Link layer packages data as a frame. The Physical layer packages data as bits. The Network layer packages data as a packet. The Transport layer packages data as a segment.

Which layer of the OSI Model provides reliable end-to-end communication services? A. Physical layer B. Transport layer C. Data Link layer D. Host layer

B. The Transport layer provides reliable end-to-end communication services. Neither the Physical layer nor the Data Link layer provides this service. The Host layer is on the TCP/IP Model, not the OSI Model.

Which of these ports does DNS use? A. TCP 23 B. TCP 25 C. UDP 53 D. UDP 69

C. Domain Name System (DNS) uses UDP port 53 when clients query the DNS server and TCP port 53 when DNS servers transfer data between each other. Telnet uses TCP port 23. Simple Mail Transfer Protocol (SMTP) uses TCP port 25. Trivial FTP (TFTP) uses UDP port 69.

Which of the following protocols is connection oriented? A. IP B. RIP C. TCP D. UDP

C. TCP is connection oriented. IP uses TCP to provide a connection-oriented session but is not connection oriented itself. RIP is a routing protocol and is not connection oriented. UDP is connectionless. Instead of establishing a session, it makes a best effort to deliver data.

Which of the following is the recommended security mechanism to use with wireless networks? A. 802.11a B. 802.11g C. 802.11i D. 802.11n

C. The 802.11i standard documents Wi-Fi Protected Access 2 (WPA2), the recommended security mechanism for wireless networks. It uses AES-based CCMP for very strong security. The other standards focus on the base frequency and speed of wireless networks, not security.

Which layer of the OSI Model handles physical addressing? A. Physical layer B. Network layer C. Data Link layer D. Transport layer

C. The Data Link layer uses physical addresses, also called hardware addresses and media access control (MAC) addresses. The Physical layer packages data as bits and doesn't use addresses. The Network layer uses IP addresses (also called logical addresses). The Transport layer doesn't use addresses but uses ports to identify traffic.

Which layer of the OSI Model packages data as a packet? A. Physical layer B. Data Link layer C. Network layer D. Transport layer

C. The Network layer packages data as a packet. The Physical layer packages data as bits. The Data Link layer packages data as a frame. The Transport layer packages data as a segment.

Which layer of the TCP/IP Model corresponds to the OSI Network layer? A. Host layer B. Application layer C. Internet layer D. Link layer

C. The TCP/IP Internet layer corresponds to the OSI Network layer. The TCP/ IP Host (or Host-to-Host) layer corresponds to the OSI Transport layer. The TCP/IP Application layer corresponds to the Application, Presentation, and Session OSI layers. The TCP/IP Link layer (also called the Network Interface or Network Access layer) corresponds to the OSI Data Link and Physical layers.

Where is a DMZ located? A. Behind the intranet firewall B. In front of the first intranet-facing firewall C. In front of the first Internet-facing firewall D. Behind the first Internet-facing firewall

D. A demilitarized zone (DMZ), or perimeter network, is located behind the first Internet-facing firewall. It is not on the private network (behind the intranet firewall) or directly on the Internet (in front of the intranet or Internet-facing firewall).

Which of the following protocols is commonly used with diagnostic utilities? A. TFTP B. RARP C. IGMP D. ICMP

D. Many diagnostic utilities such as ping, pathping, and tracert use Internet Control Message Protocol (ICMP). Administrators commonly use Trivial FTP (TFTP) to transfer configuration files to and from network devices. Reverse ARP (RARP) allows a system with a MAC address to get an IP address. The Internet Group Message Protocol (IGMP) is used for IPv4 multicasting.

Which of the following protocols is a more secure alternative for remote login? A. Telnet B. rlogin C. rexec D. SSH

D. Secure Shell (SSH) encrypts data sent over a network and is the most secure method for remotely accessing systems of the given choices. Telnet, rlogin (which is remote login), and rexec (remote execute) all send data across a network in cleartext

What is the protocol number for IPsec AH? A. 1 B. 6 C. 50 D. 51

D. The protocol number for Internet Protocol security (IPsec) Authentication Header is 51. The protocol number for IPsec Encapsulating Security Protocol (ESP) is 50. The protocol number for Internet Control Message protocol (ICMP) is 1, and the protocol number for Transmission Control Protocol (TCP) is 6.