1b - Fundamentals of Protocols

Question 1

TCP

Answer 1

Connection oriented;
Requires a stable connection between the client and the server before a message is sent.

Question 2

UDP

Answer 2

Connectionless;
Will send information without verifying someone is on the other end to receive the information - There is no guarantee of data delivery.

Question 3

Transport Protocols

Answer 3

TCP and UDP

Question 4

Used by servers in order to determine the specific protocol being used.

Answer 4

Port numbers

Question 5

FTP

Answer 5

Uses port 21 to transfer files between clients and servers;
data sent in FTP is in cleartext and is a potential security risk.

Question 6

Telnet

Answer 6

Uses port 23 and allows users to remotely log in to UNIX/Linux host;
sends usernames and passwords using cleartext and is a potential security risk.

Question 7

Secure shell (SSH)

Answer 7

Uses port 22 and a direct replacement for telnet; added encryption over the login and data sent over the connection.

Question 8

Secure copy (SCP)

Answer 8

Uses port 22 to add encryption from SSH in order to securely transfer files between network hosts.

Question 9

DNS

Answer 9

Uses port 53 to map computer names to IP addresses; is used with both TCP and UDP.

Question 10

TCP 53

Answer 10

Used for zone transfers - updates between DNS servers.

Question 11

UDP 53

Answer 11

Used for DNS queries and replies between DNS servers and client end devices.

Question 12

DHCP

Answer 12

Used to assign IP addresses automatically to clients on the network;
Uses UDP 67 and UDP 68
Uses UDP 67 to receive information from a client
Uses UDP 68 to send information to a client

Question 13

TFTP

Answer 13

Uses port 69 - UDP;
Transfers files between servers and clients without requiring a login.
Commonly used to send files to routers or workstations that don’t have a disk drive.

Question 14

HTTP

Answer 14

Uses port 80 - TCP;
Used by clients using a web browser to request information from web servers.

Question 15

SMTP

Answer 15

Uses port 25 - TCP;
Used for sending e-mail messages between servers.

Question 16

POP3

Answer 16

Uses port 110 - TCP;
Used for retrieving e-mail traffic from mail servers.

Question 17

NTP

Answer 17

Uses port 123 - UDP;
Used to synchronize timing within the network.

Question 18

IMAP

Answer 18

Uses port 143 - TCP;
Used to access and manage e-mail messages while leaving the messages stored on the e-mail server.

Question 19

SNMP

Answer 19

Uses ports 161 and 162 - UDP;
Used by applications to monitor network devices remotely.

Question 20

HTTPS

Answer 20

Uses port 443 - TCP;
A secured HTTP version providing an encrypted connection between a web server and a web client.

Question 21

RDP

Answer 21

Uses port 3389 - TCP;
A microsoft proprietary protocol that enables remote connections to other computers over an encrypted channel.

Question 22

Often referred to as the Internet model

Answer 22

TCP/IP

Question 23

TCP/IP Model

Answer 23

Link
Internet
Transport
Application

Question 24

TCP/IP: Link/Network Layer

Answer 24

Physical/MAC addressing, NICs, Switching, Cabling;
Corresponds to Physical and DLL of OSI model.

Question 25

TCP/IP: Internet Layer

Answer 25

IP packets, Logical/IP Addressing, Routers;
Corresponds to the Network Layer of OSI model.

Question 26

TCP/IP: Transport Layer

Answer 26

Corresponds to Transport and Session Layers of OSI model;
Two core protocols: TCP and UDP

Question 27

TCP/IP: Application Layer

Answer 27

Combines Application, Presentation, and Session layers of the OSI model;
Uses ports to give each application a unique number that identifies the protocol it uses.