Networking Concepts (1) Flashcards
Which of the following pairs of well-known ports are the default values you would use to configure a POP3 email client?
110 and 25
143 and 25
110 and 143
110 and 25
The default port for the Post Office Protocol (POP3) is 110. The default port for the Simple Mail Transfer Protocol (SMTP), the other protocol used by email clients, is 25. Port 143 is the default for the Internet Message Access Protocol (IMAP), a different email mailbox protocol that clients never use with POP3. Port 80 is the default for the Hypertext Transfer Protocol (HTTP), which is not used by email clients
Which of the following server applications use two well-known port numbers during a typical transaction?
SNMP
HTTP
FTP
FTP
The File Transfer Protocol (FTP) uses two port numbers. It uses the first, port 21, for a control connection that remains open during the entire client/server session. The second port, 20, is for a data connection that opens only when the protocol is actually transferring a file between the client and the server. Network Time Protocol (NTP), Simple Network Management Protocol (SNMP), and Hypertext Transfer Protocol (HTTP) all use a single port on the server
Which of the following protocols does the Ping utility use to exchange messages with another system?
UDP
TCP
ICMP
ICMP
Ping uses the Internet Control Message Protocol (ICMP) to exchange messages with other systems. ICMP is also used to return error messages to sending systems. The User Datagram Protocol (UDP) and the Transmission Control Protocol (TCP) are both transport layer protocols that carry application layer data; Ping does not use either one. The Internet Group Management Protocol (IGMP) is used to create multicast groups; Ping does not use it
Which of the following components does the port number in a transport layer protocol header identify?
A transport layer protocol
An application
A gateway
An application
The port numbers specified in a transport layer protocol header identify the application that generated the data in the packet or the application that will receive the data. Port numbers do not identify transport layer protocols, gateways, or proxy servers
Which of the following organizations is responsible for assigning the well-known port numbers used in transport layer protocol headers?
Institute for Electronic and Electrical Engineers (IEEE)
Internet Assigned Numbers Authority (IANA)
Internet Engineering Task Force (IETF)
Internet Assigned Numbers Authority (IANA)
The IANA assigns values for well-known port numbers. The IEEE publishes Ethernet standards, among many others. The IETF develops standards for Internet technologies. The ISO developed the Open Systems Interconnection (OSI) model
A client on a TCP/IP network is attempting to establish a session with a server. Which of the following correctly lists the order of Transmission Control Protocol (TCP) session establishment messages?
SYN, SYN, ACK, ACK
SYN/ACK, SYN/ACK
SYN, SYN/ACK, ACK
SYN, SYN/ACK, ACK
The TCP connection establishment exchange is a three-way handshake. The first frame contains a SYN message from the client, the second frame contains a SYN/ACK message from the server, and the last frame contains an ACK message from the client
Which of the following is the default well-known port number for the Hypertext Transfer Protocol (HTTP) used for web client/server communications?
22
20
80
80
Port 80 is the default well-known port for HTTP. Port 22 is for the Secure Shell (SSH) protocol, port 20 is for File Transfer Protocol (FTP), and 1720 is for the H.323 audio/video-conferencing protocol
The secured version of the Hypertext Transfer Protocol (HTTPS) uses a different well-known port from the unsecured version. Which of the following ports is used by HTTPS by default?
80
110
443
443
The well-known port for HTTPS is 443. Port 25 is for the Simple Mail Transfer Protocol (SMTP), port 80 is for unsecured HTTP, and port 110 is for the Post Office Protocol (POP3)
Which of the following Transmission Control Protocol (TCP) control bits is set to 1 to initiate the termination of a session?
SYN
URG
FIN
FIN
The termination phase of a TCP connection begins when either the client or the server sends a message containing the FIN control bit with a value of 1. The other control bits listed have nothing to do with the connection termination procedure, and there is no END bit
What field in the Transmission Control Protocol (TCP) Option subheader specifies the size of the largest segment a system can receive?
MSS
Window
MMS
MSS
The Maximum Segment Size (MSS) field in the TCP Options subheader specifies the size (in bytes) of the largest segment a system can receive. The Window field indicates the amount of data (in bytes) that the receiver can accept. There are no MMS or WinMS fields in a TCP header
What is the term for the combination of an IPv4 address and a port number, as in the following example: 192.168.1.3:23?
Socket
OUI
Well-known port
Socket
The term for an IPv4 address and port number in combination is socket. An organizationally unique identifier (OUI) identifies a manufacturer of networking hardware. A well-known port is a port number assigned to a specific application. A network address is the network identifier part of an IP address. A domain is a group of computers and other resources
Which of the following protocols generate messages that are carried directly within Internet Protocol (IP) datagrams, with no intervening transport layer protocol? (Choose all correct answers.)
ICMP
IGMP
SMTP
SNMP
ICMP
IGMP
Internet Control Message Protocol (ICMP) and Internet Group Management Protocol (IGMP) are unusual in that they generate messages that are encapsulated directly within IP datagrams. Nearly all of the other TCP/IP protocols, including Simple Mail Transfer Protocol (SMTP) and Simple Network Management Protocol (SNMP), are encapsulated within one of the transport layer protocols—User Datagram Protocol (UDP) or Transmission Control Protocol (TCP)—which is encapsulated in turn within an IP datagram
Which of the following protocols is used to exchange directory service information?
RDP
LDAP
SNMP
LDAP
The Lightweight Directory Access Protocol (LDAP) is an application layer protocol used for managing and accessing information stored in directory services. Remote Desktop Protocol (RDP) is used to establish a graphical remote control session with another computer. Simple Network Management Protocol (SNMP) is used to carry information gathered by management agents distributed around a network to a central management server. Server Message Block (SMB) is the primary file sharing protocol used by Windows systems
Which of the following is the primary application layer protocol used by web browsers to communicate with web servers?
HTTP
HTML
SMTP
HTTP
The Hypertext Transfer Protocol (HTTP) is the primary protocol used for web client/server communications. Hypertext Markup Language is a coding language used to create web content. Simple Mail Transfer Protocol (SMTP) and File Transfer Protocol (FTP) can both be used in web communications, but neither is the primary protocol
Which of the following protocols appears on the network as a service that client computers use to resolve names into IP addresses?
DHCP
BOOTP
DNS
DNS
The Domain Name System (DNS) is a protocol that computers on a TCP/IP network use to resolve host and domain names into the IP addresses they need to communicate. Dynamic Host Configuration Protocol (DHCP) and Bootstrap Protocol (BOOTP) are both IP address allocation protocols, and Simple Network Management Protocol (SNMP) carries information gathered by agents to a central management console
Which of the following protocols use(s) the term datagram to describe the data transfer unit it creates? (Choose all correct answers.)
Ethernet
IP
TCP
UDP
IP
UDP
The term datagram is typically used by protocols offering connectionless delivery service. The two main connectionless protocols in the TCP/IP suite are the Internet Protocol (IP) and the User Datagram Protocol (UDP), both of which use the term datagram. Ethernet uses the term frame, and Transmission Control Protocol (TCP) uses segment
What is the native file sharing protocol used on all Microsoft Windows operating systems?
Network File System (NFS)
File Transfer Protocol (FTP)
Server Message Block (SMB)
Server Message Block (SMB)
The default file sharing protocol used on all Windows operating systems is SMB. HTTP is the native protocol used by web clients and servers. NFS is the native file sharing protocol used on Unix/Linux networks. FTP is a protocol used for transferring files from one system to another. LDAP is a protocol for transmitting directory service information
When analyzing captured TCP/IP packets, which of the following control bits must you look for in the Transmission Control Protocol (TCP) header to determine whether the receiving host has successfully received the sending host’s data?
ACK
FIN
PSH
ACK
The receiving host uses the ACK bit to notify the sending host that it has successfully received data. The other control bits are not used to acknowledge receipt of information
Which of the following terms describes the Transmission Control Protocol (TCP) exchange that establishes a connection prior to the transmission of any data?
Initialization exchange
Connection establishment
Three-way handshake
Three-way handshake
Two systems establishing a TCP connection exchange three messages before they begin transmitting data. The exchange of these synchronization messages is referred to as a three-way handshake. The other terms listed are not formally used to describe this exchange
Alice has been instructed to install 100 Windows workstations, and she is working on automating the process by configuring the workstations to use PXE boots. Each workstation therefore must obtain an IP address from a DHCP server and download a boot image file from a TFTP server. Which of the following well-known ports must Alice open on the firewall separating the workstations from the servers? (Choose all correct answers.)
65
66
67
68
69
67
68
69
Dynamic Host Configuration Protocol (DHCP) servers use port numbers 67 and 68. The Trivial File Transfer Protocol (TFTP) uses port number 69. Neither protocol uses port 65 or 66
Which of the following explanations best describes the function of a Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) port number?
The port number indicates to the receiver that the sender can activate a specific port only.
The port number is used by both the sender and the receiver to identify the application that generated the information in the datagram.
The port number is used only by the receiver to indicate the application process running on the sender.
The port number is used by both the sender and the receiver to identify the application that generated the information in the datagram.
TCP ports and UDP ports identify the application protocol or process that generated the information in a datagram. Client ports are chosen randomly from the range 1024 through 65,534. Server ports are well-known and are chosen from the range 1 through 1023
What is the valid range of numbers for the ephemeral client ports used by the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)?
1023 through 65534
1 through 1024
49152 through 65535
49152 through 65535
Ephemeral client ports fall in the range of 49152 through 65535. Well-known TCP and UDP server ports fall in the range of 1 through 1023. Registered port numbers fall in the range from 1024 to 49151
Which of the following statements about the User Datagram Protocol (UDP) are true? (Choose all correct answers.)
UDP does not use packet sequencing and acknowledgments.
UDP uses packet sequencing and acknowledgments.
UDP is a connection-oriented protocol.
UDP is a connectionless protocol.
UDP has an 8-byte header.
UDP has a 20-byte header.
UDP does not use packet sequencing and acknowledgments.
UDP is a connectionless protocol.
UDP has an 8-byte header.
UDP is a connectionless transport layer protocol. It has a small, 8-byte header and does not use packet sequencing or acknowledgments
Which of the following port values are used by the File Transfer Protocol (FTP)? (Choose all correct answers.)
21
23
20
53
21
53
FTP uses two ports: one for control messages (port 21) and one for data transfers (port 20). Port 23 is used by Telnet. Port 53 is used by the Domain Name System (DNS). Port 69 is used by the Trivial File Transfer Protocol (TFTP)
Which of the following protocols provides connectionless delivery service at the transport layer of the Open Systems Interconnection (OSI) model?
TCP
HTTP
UDP
UDP
The User Datagram Protocol (UDP) provides connectionless service at the transport layer. TCP provides connection-oriented service at the transport layer. HTTP is an application layer protocol, and ARP is a data link layer protocol
