CISA 2306 - CH 02

With TCP, a data session is established through a three-step process. This is known as a three-way _____.

This is known as a three-way handshake.

When TCP wants to open a connection with another host, it follows this procedure:

1. It sends a message called a SYN to the target host. 2. The target host opens a connection for the request and sends back an acknowledgment message called an ACK (or SYN ACK). 3. The host that originated the request sends back another acknowledgment, saying that it has received the ACK message and that the session is ready to be used to transfer data.

The OSI seven-layer model: (Please Do Not Throw Sausage Pizza Away) (All People Seem To Need Data Processing)

1. Physical 2. Data Link 3. Network 4. Transport 5. Session 6. Presentation 7. Application

At what layer of the OSI model do HTTP and SSH map?

HTTP and SSH (along with many other protocols) map to the application layer of the OSI model.

What ports do the HTTPS, RDP, and DHCP protocols use?

HTTPS uses port 443, RDP uses port 3389, and DHCP uses ports 67 and 68.

By default, which protocol uses port 68? A. DHCP B. DNS C. SMB D. SMTP

A. DHCP uses port 68 by default (along with 67). DNS uses port 53, SMB uses 445, and SMTP uses port 25.

What are logical groupings of SNMP systems known as? A. Communities B. Pairs C. Mirrors D. Nodes

A. SNMP communities are logical groupings of systems. When a system is configured as part of a community, it communicates only with other devices that have the same community name.

TCP is an example of what kind of transport protocol? A. Connection oriented B. Connection reliant C. Connection dependent D. Connectionless

A. TCP is an example of a connection-oriented transport protocol. UDP is an example of a connectionless protocol. Connection reliant and connection dependent are not terms commonly associated with protocols.

Which of the following is not a common packet sent during the normal DHCP process? A. DHCPACK B. DHCPPROVE C. DHCPDISCOVER D. DHCPOFFER

B. DHCPPROVE is not a common packet. The other choices presented (DHCPACK, DHCPDISCOVER, and DHCPOFFER) are part of the normal process.

What are SNMP databases called? A. HOSTS B. MIBs C. WINS D. Agents

B. SNMP uses databases of information called MIBs to define what parameters are accessible, which of the parameters are readonly, and which can be set.

Which DNS record is most commonly used to map hostnames to an IP address for a host with IPv6? A. A B. AAAA C. MX D. PTR

B. The AAAA record is most commonly used to map hostnames to an IP address for a host with IPv6. The A record is not used for this purpose. MX identifies the mail exchanger, and PTR is used for reverse lookup.

Which of the following OSI layers is responsible for establishing connections between two devices? A. Network B. Transport C. Session D. Data link

B. The transport layer is responsible for establishing a connection between networked devices. The network layer is most commonly associated with route discovery and datagram delivery. Protocols at the session layer synchronize the data exchange between applications on separate devices. Protocols at the data link layer perform error detection and handling for the transmitted signals and define the method by which the medium is accessed.

At which OSI layer does an AP operate? A. Network B. Physical C. Data link D. Session

C. A wireless access point (AP) operates at the data link layer of the OSI model. An example of a network layer device is a router. An example of a physical layer device is a hub. Session layer components normally are software, not hardware.

One of the programmers has asked that DHCP always issue his workstation the same IP address. What feature of DHCP enables you to accomplish this? A. Stipulation B. Rider C. Reservation D. Provision

C. Reservations are specific addresses reserved for clients.

Which DNS record stores additional hostnames, or aliases, for hosts in the domain? A. ALSO B. ALIAS C. CNAME D. PTR

C. The CNAME record stores additional hostnames, or aliases, for hosts in the domain. There is not an ALSO record or ALIAS, and PTR is used for reverse lookups.

During a discussion with your ISP's technical support representative, she mentions that you might have been using the wrong FQDN. Which TCP/IP-based network service is she referring to? A. DHCP B. WINS C. SNMP D. DNS

D. DNS is a system that resolves hostnames to IP addresses. The term FQDN is used to describe the entire hostname. None of the other services use FQDNs.

What is the function of NTP? A. It provides a mechanism for the sharing of authentication information. B. It is used to access shared folders on a Linux system. C. It is used to communicate utilization information to a central manager. D. It is used to communicate time synchronization information between systems.

D. NTP is used to communicate time-synchronization information between devices. Network File System (NFS) is a protocol typically associated with accessing shared folders on a Linux system. Utilization information is communicated to a central management system most commonly by using SNMP.

Which of the following protocols offers guaranteed delivery? A. FTP B. POP C. IP D. TCP

D. TCP is a connection-oriented protocol that guarantees delivery of data. FTP is a protocol used to transfer large blocks of data. POP stands for Post Office Protocol and is not the correct choice. IP is a network layer protocol responsible for tasks such as addressing and route discovery.

What is the name used for ranges of IP addresses available within DHCP?

Within DHCP, ranges of IP addresses are known as scopes.

Choose Device Layer: 1. Hub 2. Wireless bridge 3. Switch 4. Router 5. NIC 6. Access point (AP)

1. Physical (Layer 1) 2. Data link (Layer 2) 3. Data link (Layer 2) 4. Network (Layer 3) 5.Data link (Layer 2) 6. Data link (Layer 2)

Which of the following are considered transport protocols? (Choose the two best answers.) A. TCP B. IP C. UDP D. THC

A and C. Both TCP and UDP are transport protocols. IP is a network protocol, and THC is not a valid protocol.

What are two features supported in SNMPv3 and not previous versions? A. Authentication B. Dynamic mapping C. Platform independence D. Encryption

A and D. SNMPv3 supports authentication and encryption.

Which of the following are sublayers of the data link layer? (Choose two.) A. MAC B. LCL C. Session D. LLC

A and D. The data link layer is broken into two distinct sublayers: Media Access Control (MAC) and Logical Link Control (LLC). LCL is not a valid term. Session is another of the OSI model layers.

At which OSI layers can a switch operate? (Choose two.) A. Layer 1 B. Layer 2 C. Layer 3 D. Layer 4

B and C. A switch uses the MAC addresses of connected devices to make its forwarding decisions. Therefore, it is called a data link, or Layer 2, network device. It can also operate at Layer 3 or be a multilayer switch. Devices or components that operate at Layer 1 typically are media based, such as cables or connectors. Layer 4 components typically are software based, not hardware based.

What happens to data as it moves from the upper to the lower layers of the OSI model on a host system? A. The header and trailer are stripped off through decapsulation. B. The data is sent in groups of segments that require two acknowledgments. C. The data moves from the physical layer to application layer. D. It is encapsulated with a header at the beginning and a trailer at the end.

D. As data moves down the model (and through the devices on that host), it is encapsulated with a header added to the beginning and a trailer to the end. Once the data arrives at the receiving host, it moves up the model (and through the devices) and is decapsulated in that the header and trailer are stripped off as it moves up. In a windowing environment, data is sent in groups of segments that require only one acknowledgment. On the sending host system, data moves from the application layer down to the physical layer. On the receiving system, data moves from the physical layer upwards to the application layer.

Physical Layer describes:

Defines the physical structure of the network and the topology. - Hardware - Topology

What is dynamic DNS?

Dynamic DNS is a newer system that enables hosts to be dynamically registered with the DNS server.

Network Layer

Handles the discovery of destination systems and addressing. Provides the mechanism by which data can be passed and routed from one network system to another. When you're working with networks, routes can be configured in two ways: statically or dynamically. In a static routing environment, routes are manually added to the routing tables. In a dynamic routing environment, routing protocols such as Routing Information Protocol (RIP) and Open Shortest Path First (OSPF) are used. These protocols communicate routing information between networked devices on the network. Other important network layer protocols include Internet Protocol (IP), Address Resolution Protocol (ARP), Reverse Address Resolution Protocol (RARP), Asynchronous Transfer Mode (ATM), Intermediate System-to-Intermediate System (IS-IS), IP Security (IPSec), Internet Control Message Protocol (ICMP), and Multiprotocol Label Switching (MPLS).

Application Layer

Provides access to the network for applications. The application layer defines the processes that enable applications to use network services. For example, if an application needs to open a file from a network drive, the functionality is provided by components that reside at the application layer. Protocols defined at the application layer include Secure Shell (SSH), Border Gateway Protocol (BGP), Dynamic Host Configuration Protocol (DHCP), Domain Name System (DNS), Network Time Protocol (NTP), Real-time Transport Protocol (RTP), Session Initiation Protocol (SIP), Simple Mail Transfer Protocol (SMTP), Server Message Block (SMB), File Transfer Protocol (FTP), Hypertext Transfer Protocol (HTTP), Hypertext Transfer Protocol Secure (HTTPS), Internet Message Access Protocol (IMAP), and Post Office Protocol version 3 (POP3).

Transport Layer

Provides connection services between the sending and receiving devices and ensures reliable data delivery. Manages flow control through buffering or windowing. Provides segmentation, error checking, and service identification. Mechanism to transport data - Error checking - Service addressing - Segmentation Data Flow -Buffering - Windowing

Data Link Layer describes:

Provides error detection and correction. Uses two distinct sublayers: the Media Access Control (MAC) and Logical Link Control (LLC) layers. Identifies the method by which media are accessed. Defines hardware addressing through the MAC sublayer. - Media Access Control layer - Logical Link Control layer

The SSH protocol is a more secure alternative to what protocol?

SSH is a more secure alternative to Telnet.

Session Layer

Synchronizes the data exchange between applications on separate devices. The session layer is responsible for managing and controlling the synchronization of data between applications on two devices. It does this by establishing, maintaining, and breaking sessions. Whereas the transport layer is responsible for setting up and maintaining the connection between the two nodes, the session layer performs the same function on behalf of the application. Protocols that operate at the session layer include NetBIOS, Network File System (NFS), and Server Message Block (SMB).

Within DNS, what is the domain name, along with any subdomains, called?

The domain name, along with any subdomains, is called the fully qualified domain name (FQDN) because it includes all the components from the top of the DNS namespace to the host.

What FTP command uploads multiple files to the remote host?

The mput command uploads multiple files to the remote host in FTP.

Which layer of the OSI model converts data from the application layer into a format that can be sent over the network?

The presentation layer converts data from the application layer into a format that can be sent over the network. It also converts data from the session layer into a format the application layer can understand.

Presentation Layer

Translates data from the format used by applications into one that can be transmitted across the network. Handles encryption and decryption of data. Provides compression and decompression functionality. Formats data from the application layer into a format that can be sent over the network. - Graphic files - Text and data - Sound/

True or false: Transport protocols, such as UDP, map to the transport layer of the OSI model and are responsible for transporting data across the network.

True. Transport protocols map to the transport layer of the OSI model and are responsible for transporting data across the network. UDP is a transport protocol.

What is the name of the packet on a system configured to use DHCP broadcasts when it comes onto the network?

When a system configured to use DHCP comes onto the network, it broadcasts a special packet that looks for a DHCP server. This packet is known as the DHCPDISCOVER packet.

The OSI model can be used as

a bottom-to-top troubleshooting tool.

Removing protocol information to data as it passes through layers is known as _________.

decapsulation

Adding protocol information to data as it passes through layers is known as ________.

encapsulation