The document discusses File Transfer Protocol (FTP) and Trivial File Transfer Protocol (TFTP). FTP uses two TCP connections, one for control and one for data transfer. It processes client commands to establish communication and transfer files. TFTP is simpler, using UDP to quickly transfer files without FTP's complexity. It is used to download configuration files when initializing devices.
The document discusses the architecture of the World Wide Web and HTTP. It defines key concepts like hypertext, web clients and servers, URLs, and different types of web documents (static, dynamic, active). It also explains HTTP transactions in detail, including request and response messages, methods like GET and POST, persistent and non-persistent connections, and the use of cookies. Web caching using proxy servers is also introduced.
File Transfer Protocol (FTP) allows copying files between systems over TCP/IP. It uses two TCP connections, one for control commands and another for transferring file data. FTP solves problems like different file naming conventions or text representations between systems. It supports anonymous access, security, and transferring different file types like binary images. Examples show the FTP session process and commands for listing directories, retrieving files, and uploading files.
The document discusses the architecture and components of the World Wide Web and HTTP. It covers clients (browsers), servers, URLs, cookies, and the three categories of web documents: static, dynamic, and active. It also explains HTTP transactions, including request and response messages, status codes, headers, and examples of GET and POST methods. Key concepts covered are browsers, servers, URLs, cookies, static documents using HTML, dynamic documents using CGI and scripts, active documents using Java applets and scripts, and the functioning of HTTP.
FTP uses two TCP connections - a control connection on port 21 and a data connection, usually on port 20. The client uses the control connection to send commands to the server and receive responses, while the data connection is used to transfer files. The document discusses FTP connections and command processing, the three main types of file transfers, anonymous FTP, security considerations for FTP, and the simpler TFTP protocol.
This document discusses two file transfer protocols: FTP and TFTP. FTP uses TCP and requires two connections - one for control and one for data transfer. It addresses issues like different file formats between systems. TFTP is simpler, using UDP instead of TCP. It is used to quickly download small bootstrap and configuration files when systems boot. TFTP uses well-known port 69 while FTP uses ports 20 and 21. The document provides diagrams illustrating the connections and operations of each protocol.
This document provides an overview of the OSI model and TCP/IP protocol suite. It describes the seven-layer OSI model and how the TCP/IP protocol suite corresponds to the first five layers. Each layer of the OSI model is briefly defined. The document also discusses the three types of addresses used in TCP/IP: physical, logical (IP), and port addresses. Later versions of the IP protocol, including versions 4, 5, and 6, are also introduced.
The document discusses the architecture of the World Wide Web and HTTP. It defines key concepts like hypertext, web clients and servers, URLs, and different types of web documents (static, dynamic, active). It also explains HTTP transactions in detail, including request and response messages, methods like GET and POST, persistent and non-persistent connections, and the use of cookies. Web caching using proxy servers is also introduced.
File Transfer Protocol (FTP) allows copying files between systems over TCP/IP. It uses two TCP connections, one for control commands and another for transferring file data. FTP solves problems like different file naming conventions or text representations between systems. It supports anonymous access, security, and transferring different file types like binary images. Examples show the FTP session process and commands for listing directories, retrieving files, and uploading files.
The document discusses the architecture and components of the World Wide Web and HTTP. It covers clients (browsers), servers, URLs, cookies, and the three categories of web documents: static, dynamic, and active. It also explains HTTP transactions, including request and response messages, status codes, headers, and examples of GET and POST methods. Key concepts covered are browsers, servers, URLs, cookies, static documents using HTML, dynamic documents using CGI and scripts, active documents using Java applets and scripts, and the functioning of HTTP.
FTP uses two TCP connections - a control connection on port 21 and a data connection, usually on port 20. The client uses the control connection to send commands to the server and receive responses, while the data connection is used to transfer files. The document discusses FTP connections and command processing, the three main types of file transfers, anonymous FTP, security considerations for FTP, and the simpler TFTP protocol.
This document discusses two file transfer protocols: FTP and TFTP. FTP uses TCP and requires two connections - one for control and one for data transfer. It addresses issues like different file formats between systems. TFTP is simpler, using UDP instead of TCP. It is used to quickly download small bootstrap and configuration files when systems boot. TFTP uses well-known port 69 while FTP uses ports 20 and 21. The document provides diagrams illustrating the connections and operations of each protocol.
This document provides an overview of the OSI model and TCP/IP protocol suite. It describes the seven-layer OSI model and how the TCP/IP protocol suite corresponds to the first five layers. Each layer of the OSI model is briefly defined. The document also discusses the three types of addresses used in TCP/IP: physical, logical (IP), and port addresses. Later versions of the IP protocol, including versions 4, 5, and 6, are also introduced.
Transfer to my name is the strongest namaste 🙏🏻 I am happy to hear from the file is the strongest namaste I have to do you have to do you have to do you think I. Namaste I have to do you have to do you have to do you have to do you have to do it for you to be a good day ahead with the .
The document discusses the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). It provides details on:
- UDP is a connectionless protocol that provides unreliable datagram delivery. It has less overhead than TCP but also less features.
- TCP is a connection-oriented protocol that provides reliable, ordered delivery of streams of bytes. It uses three-way handshake for connection establishment, acknowledgments, and network congestion/flow control.
- Both protocols use port numbers to identify applications on hosts. TCP segments carry sequence numbers and acknowledgment numbers to support reliability.
The document provides in-depth explanations of features like multiplexing, error/flow control, congestion control, and how
This document discusses transport layer protocols. It begins by introducing the three main transport layer protocols in TCP/IP - UDP, TCP, and SCTP. It then focuses on UDP and TCP, explaining their packet formats, features, and how they provide different types of services. For UDP, it describes how it is a simple connectionless protocol suited for applications that require low latency. For TCP, it explains how it provides reliable, in-order byte streams using connection establishment and maintenance features like flow control, congestion control, and error recovery. The document contains examples and diagrams to illustrate these concepts.
TCP and UDP are transport layer protocols that package and deliver data between applications. TCP provides reliable, ordered delivery through connection establishment and packet sequencing. UDP provides faster, unreliable datagram delivery without connections. Common applications using TCP include HTTP, FTP, and SMTP. Common UDP applications include DNS, DHCP, and streaming media.
This document discusses the User Datagram Protocol (UDP) which provides a connectionless mode of communication between applications on hosts in an IP network. It describes the format of UDP packets, how UDP checksums are calculated, and UDP's operation including encapsulation, queuing, and demultiplexing. Examples are provided to illustrate how a UDP control block table and queues are used to handle incoming and outgoing UDP packets. The document also discusses when UDP is an appropriate protocol to use compared to TCP.
This document discusses the User Datagram Protocol (UDP) which provides connectionless and unreliable data transmission between applications. It covers UDP packet formats, checksum calculation, operation including encapsulation and multiplexing, appropriate uses of UDP, and the modules involved in a UDP implementation including control blocks, input/output queues, and tables. Examples are provided to illustrate how UDP handles packet reception and association with processes.
Cisco discovery d homesb module 6 - v.4 in english.igede tirtanata
The document contains questions and answers about networking concepts like the TCP/IP model, IP addressing, protocols, and the OSI model. Specifically:
- www.cisco.com represents the domain name of a web server, not an IP address, router interface, or other network details.
- An email server would use IMAP to allow email clients to access email messages stored on the server.
- In a corporate environment, a DHCP server would most likely be used first by network clients to obtain an IP address.
- The layers of the TCP/IP model are application, transport, internet, and network access.
- The OSI reference model layers are physical, data link, network, transport
The document discusses file transfer protocols FTP and TFTP. It provides an overview of FTP, including the connections needed, commands, responses, and file transfer process. TFTP is introduced as a simpler file transfer protocol than FTP that uses UDP instead of TCP and lacks sophisticated features. Examples of file transfers using FTP and TFTP are presented along with message formats and error codes.
SCTP is a transport layer protocol that provides reliable message-oriented communication with features like multiple streams, multihoming, and network-level fault tolerance. It establishes associations between endpoints, transfers data in packets containing chunks, and uses acknowledgments and retransmissions to ensure reliable delivery. SCTP supports flow and error control like TCP but adds new capabilities due to its message-oriented design and ability to interface with multiple IP addresses.
2.4 Write a stream –based echo server and a client sending message t.pdfexcellentmobiles
2.4 Write a stream –based echo server and a client sending message to it, and receiving back
each message in turn until the client terminates the connection. Hint: Modify the stream-based
TCP client and server programs in this chapter or similar programs to transfer multiple messages
back and forth.
Solution
The Transmission Control Protocol (TCP) is a stream-based method of network communication.
And one of the main protocol of Internet Protocol suite.
TCP provides an interface to network communications that is radically different from the USER
datagram Protocol(UDP).
The properties of TCP make it highly attractive to network programmers and it simplifies
network communication by removing many of the obstacles of UDP, such as ordering of packets
and packet loss.
TCP focuses instead on establishing a network connection, through which a stream of bytes may
be sent and received.
It establishes a \"virtual connection\" between two machines, through which stream of data may
be sent.
TCP uses a lowel-level communications protocol, the internet protocol to establish the
connection between machines.This connection provides an interface that allows stream of bytes
to be sent and received and to convert the data into IP datagram packets.
Simple Echo Server Program:
import socket
host = \' \'
port = 5000
backlog = 1024
s = socket.socket(socket.AF-INET, socket.SOCK-STREAM)
s.bind ((host,port))
s.listen(backlog)
while 1:
client, address = s. accept()
data = client.recv(size)
if data;
client.send(data)
client.close()
TCP ECHO CLIENT USING STREAMS:
import asyncio
@asyncio.coroutine
def tcp-echo-client(message, loop);
reader, writer = yield from asyncio.open-connection(loop = loop)
printf(\"send:% message)
writer.write(message.encode())
data = yield from reader.read(100)
print(\'received: %r\' %data.decode())
print(\'close the socket\')
writer.close()
message = \'Hello World\'
loop = asyncio.get-event-loop()
loop.run-until-complete-echo-client(message,loop)
loop.close().
Here are explanations of the requested concepts:
1. SMTP (Simple Mail Transfer Protocol):
- Used for sending and receiving email messages between servers
- Works on TCP port 25
- Client (email sender) connects to SMTP server and sends the email
- SMTP server then handles delivering the email to recipient's SMTP server
2. POP (Post Office Protocol):
- Used for retrieving email from a remote server to a local machine
- Works on TCP port 110 (POP3)
- User must first authenticate with their username and password
- POP downloads all emails from the server to the local machine
- Emails are then deleted from the server by default
3. IMAP (Internet Message Access Protocol):
HTTP/2 and QUICK protocols. Optimizing the Web stack for HTTP/2 erapeychevi
The new HTTP/2 protocol which is going to replace HTTP 1.1 was finished on February. Together with it, QUIC is being developed rapidly. Discover why are they so important for the Web and how will they influence the way we optimize the Web stack for the HTTP/2 era.
The document provides an overview of the TCP/IP protocol suite and OSI model. It discusses the seven layers of the OSI model and their functions. It then explains that the TCP/IP protocol suite consists of five layers that correspond to the bottom four layers of the OSI model, with the top three OSI layers represented by a single application layer in TCP/IP. The document goes on to cover addressing in TCP/IP networks, different versions of the IP protocol, and methods for connecting local area networks.
Transport Layer: Transport Layer Protocols- User Datagram Protocol- TCP: TCP Services TCP features- Windows in TCP- Flow Control- Error Control- TCP Congestion Control- TCP timers
This document summarizes the transport layer and the key protocols TCP and UDP. It explains that the transport layer establishes communication sessions between applications, segments data for transmission, and ensures proper delivery. TCP provides reliable, ordered delivery using acknowledgements, while UDP is simpler but unreliable. Popular applications of each are discussed, showing how TCP and UDP address different network requirements.
This document provides an overview of TCP/IP and related networking concepts. It begins with an introduction to TCP/IP, including its history and the DoD networking model on which it is based. The document then describes several important protocols at each layer of the DoD model, including application layer protocols like HTTP, DNS, and DHCP. It concludes with an explanation of IP addressing and the different classes of IPv4 addresses.
The document discusses the application layer in computer networking. It covers key concepts like client-server architecture, peer-to-peer architecture, and hybrid architectures. It also describes several important application layer protocols, including HTTP, FTP, SMTP, POP3, IMAP, and DNS.
The document discusses the OSI model and TCP/IP protocol suite. It provides an overview of the 7 layers of the OSI model and the functions of each layer. It also describes the layers of the TCP/IP protocol suite and how it maps to the OSI model. The document outlines the different types of addresses used in TCP/IP including physical, logical, and port addresses. Examples are provided to illustrate how data is encapsulated and addressed as it passes through the different layers of the OSI model and TCP/IP protocol suite.
The document discusses several application layer protocols used for remote access and file transfer over TCP/IP networks, including HTTP, Telnet, and SSH. It provides the following key details:
1. HTTP is the application layer protocol that defines how web clients and servers communicate to transfer web pages and other content. It allows clients to send requests for files and receive responses from servers.
2. Telnet is an older protocol that allows establishing terminal sessions with remote systems, making the local terminal appear like it is directly connected to the remote system. It uses options negotiation to configure settings like echoing of characters.
3. SSH was developed as a more secure replacement for Telnet, using encryption for authentication and data transfer
The document summarizes the OSI model and TCP/IP protocol suite. It describes the seven layers of the OSI model and their functions. It then explains that the TCP/IP protocol suite has five layers that correspond to the bottom four layers of the OSI model, with the top three OSI layers combined into a single application layer in TCP/IP. It also discusses the different types of addresses used in each layer, including physical, logical, and port addresses.
Transfer to my name is the strongest namaste 🙏🏻 I am happy to hear from the file is the strongest namaste I have to do you have to do you have to do you think I. Namaste I have to do you have to do you have to do you have to do you have to do it for you to be a good day ahead with the .
The document discusses the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). It provides details on:
- UDP is a connectionless protocol that provides unreliable datagram delivery. It has less overhead than TCP but also less features.
- TCP is a connection-oriented protocol that provides reliable, ordered delivery of streams of bytes. It uses three-way handshake for connection establishment, acknowledgments, and network congestion/flow control.
- Both protocols use port numbers to identify applications on hosts. TCP segments carry sequence numbers and acknowledgment numbers to support reliability.
The document provides in-depth explanations of features like multiplexing, error/flow control, congestion control, and how
This document discusses transport layer protocols. It begins by introducing the three main transport layer protocols in TCP/IP - UDP, TCP, and SCTP. It then focuses on UDP and TCP, explaining their packet formats, features, and how they provide different types of services. For UDP, it describes how it is a simple connectionless protocol suited for applications that require low latency. For TCP, it explains how it provides reliable, in-order byte streams using connection establishment and maintenance features like flow control, congestion control, and error recovery. The document contains examples and diagrams to illustrate these concepts.
TCP and UDP are transport layer protocols that package and deliver data between applications. TCP provides reliable, ordered delivery through connection establishment and packet sequencing. UDP provides faster, unreliable datagram delivery without connections. Common applications using TCP include HTTP, FTP, and SMTP. Common UDP applications include DNS, DHCP, and streaming media.
This document discusses the User Datagram Protocol (UDP) which provides a connectionless mode of communication between applications on hosts in an IP network. It describes the format of UDP packets, how UDP checksums are calculated, and UDP's operation including encapsulation, queuing, and demultiplexing. Examples are provided to illustrate how a UDP control block table and queues are used to handle incoming and outgoing UDP packets. The document also discusses when UDP is an appropriate protocol to use compared to TCP.
This document discusses the User Datagram Protocol (UDP) which provides connectionless and unreliable data transmission between applications. It covers UDP packet formats, checksum calculation, operation including encapsulation and multiplexing, appropriate uses of UDP, and the modules involved in a UDP implementation including control blocks, input/output queues, and tables. Examples are provided to illustrate how UDP handles packet reception and association with processes.
Cisco discovery d homesb module 6 - v.4 in english.igede tirtanata
The document contains questions and answers about networking concepts like the TCP/IP model, IP addressing, protocols, and the OSI model. Specifically:
- www.cisco.com represents the domain name of a web server, not an IP address, router interface, or other network details.
- An email server would use IMAP to allow email clients to access email messages stored on the server.
- In a corporate environment, a DHCP server would most likely be used first by network clients to obtain an IP address.
- The layers of the TCP/IP model are application, transport, internet, and network access.
- The OSI reference model layers are physical, data link, network, transport
The document discusses file transfer protocols FTP and TFTP. It provides an overview of FTP, including the connections needed, commands, responses, and file transfer process. TFTP is introduced as a simpler file transfer protocol than FTP that uses UDP instead of TCP and lacks sophisticated features. Examples of file transfers using FTP and TFTP are presented along with message formats and error codes.
SCTP is a transport layer protocol that provides reliable message-oriented communication with features like multiple streams, multihoming, and network-level fault tolerance. It establishes associations between endpoints, transfers data in packets containing chunks, and uses acknowledgments and retransmissions to ensure reliable delivery. SCTP supports flow and error control like TCP but adds new capabilities due to its message-oriented design and ability to interface with multiple IP addresses.
2.4 Write a stream –based echo server and a client sending message t.pdfexcellentmobiles
2.4 Write a stream –based echo server and a client sending message to it, and receiving back
each message in turn until the client terminates the connection. Hint: Modify the stream-based
TCP client and server programs in this chapter or similar programs to transfer multiple messages
back and forth.
Solution
The Transmission Control Protocol (TCP) is a stream-based method of network communication.
And one of the main protocol of Internet Protocol suite.
TCP provides an interface to network communications that is radically different from the USER
datagram Protocol(UDP).
The properties of TCP make it highly attractive to network programmers and it simplifies
network communication by removing many of the obstacles of UDP, such as ordering of packets
and packet loss.
TCP focuses instead on establishing a network connection, through which a stream of bytes may
be sent and received.
It establishes a \"virtual connection\" between two machines, through which stream of data may
be sent.
TCP uses a lowel-level communications protocol, the internet protocol to establish the
connection between machines.This connection provides an interface that allows stream of bytes
to be sent and received and to convert the data into IP datagram packets.
Simple Echo Server Program:
import socket
host = \' \'
port = 5000
backlog = 1024
s = socket.socket(socket.AF-INET, socket.SOCK-STREAM)
s.bind ((host,port))
s.listen(backlog)
while 1:
client, address = s. accept()
data = client.recv(size)
if data;
client.send(data)
client.close()
TCP ECHO CLIENT USING STREAMS:
import asyncio
@asyncio.coroutine
def tcp-echo-client(message, loop);
reader, writer = yield from asyncio.open-connection(loop = loop)
printf(\"send:% message)
writer.write(message.encode())
data = yield from reader.read(100)
print(\'received: %r\' %data.decode())
print(\'close the socket\')
writer.close()
message = \'Hello World\'
loop = asyncio.get-event-loop()
loop.run-until-complete-echo-client(message,loop)
loop.close().
Here are explanations of the requested concepts:
1. SMTP (Simple Mail Transfer Protocol):
- Used for sending and receiving email messages between servers
- Works on TCP port 25
- Client (email sender) connects to SMTP server and sends the email
- SMTP server then handles delivering the email to recipient's SMTP server
2. POP (Post Office Protocol):
- Used for retrieving email from a remote server to a local machine
- Works on TCP port 110 (POP3)
- User must first authenticate with their username and password
- POP downloads all emails from the server to the local machine
- Emails are then deleted from the server by default
3. IMAP (Internet Message Access Protocol):
HTTP/2 and QUICK protocols. Optimizing the Web stack for HTTP/2 erapeychevi
The new HTTP/2 protocol which is going to replace HTTP 1.1 was finished on February. Together with it, QUIC is being developed rapidly. Discover why are they so important for the Web and how will they influence the way we optimize the Web stack for the HTTP/2 era.
The document provides an overview of the TCP/IP protocol suite and OSI model. It discusses the seven layers of the OSI model and their functions. It then explains that the TCP/IP protocol suite consists of five layers that correspond to the bottom four layers of the OSI model, with the top three OSI layers represented by a single application layer in TCP/IP. The document goes on to cover addressing in TCP/IP networks, different versions of the IP protocol, and methods for connecting local area networks.
Transport Layer: Transport Layer Protocols- User Datagram Protocol- TCP: TCP Services TCP features- Windows in TCP- Flow Control- Error Control- TCP Congestion Control- TCP timers
This document summarizes the transport layer and the key protocols TCP and UDP. It explains that the transport layer establishes communication sessions between applications, segments data for transmission, and ensures proper delivery. TCP provides reliable, ordered delivery using acknowledgements, while UDP is simpler but unreliable. Popular applications of each are discussed, showing how TCP and UDP address different network requirements.
This document provides an overview of TCP/IP and related networking concepts. It begins with an introduction to TCP/IP, including its history and the DoD networking model on which it is based. The document then describes several important protocols at each layer of the DoD model, including application layer protocols like HTTP, DNS, and DHCP. It concludes with an explanation of IP addressing and the different classes of IPv4 addresses.
The document discusses the application layer in computer networking. It covers key concepts like client-server architecture, peer-to-peer architecture, and hybrid architectures. It also describes several important application layer protocols, including HTTP, FTP, SMTP, POP3, IMAP, and DNS.
The document discusses the OSI model and TCP/IP protocol suite. It provides an overview of the 7 layers of the OSI model and the functions of each layer. It also describes the layers of the TCP/IP protocol suite and how it maps to the OSI model. The document outlines the different types of addresses used in TCP/IP including physical, logical, and port addresses. Examples are provided to illustrate how data is encapsulated and addressed as it passes through the different layers of the OSI model and TCP/IP protocol suite.
The document discusses several application layer protocols used for remote access and file transfer over TCP/IP networks, including HTTP, Telnet, and SSH. It provides the following key details:
1. HTTP is the application layer protocol that defines how web clients and servers communicate to transfer web pages and other content. It allows clients to send requests for files and receive responses from servers.
2. Telnet is an older protocol that allows establishing terminal sessions with remote systems, making the local terminal appear like it is directly connected to the remote system. It uses options negotiation to configure settings like echoing of characters.
3. SSH was developed as a more secure replacement for Telnet, using encryption for authentication and data transfer
The document summarizes the OSI model and TCP/IP protocol suite. It describes the seven layers of the OSI model and their functions. It then explains that the TCP/IP protocol suite has five layers that correspond to the bottom four layers of the OSI model, with the top three OSI layers combined into a single application layer in TCP/IP. It also discusses the different types of addresses used in each layer, including physical, logical, and port addresses.
Meet up Milano 14 _ Axpo Italia_ Migration from Mule3 (On-prem) to.pdfFlorence Consulting
Quattordicesimo Meetup di Milano, tenutosi a Milano il 23 Maggio 2024 dalle ore 17:00 alle ore 18:30 in presenza e da remoto.
Abbiamo parlato di come Axpo Italia S.p.A. ha ridotto il technical debt migrando le proprie APIs da Mule 3.9 a Mule 4.4 passando anche da on-premises a CloudHub 1.0.
APNIC Foundation, presented by Ellisha Heppner at the PNG DNS Forum 2024APNIC
Ellisha Heppner, Grant Management Lead, presented an update on APNIC Foundation to the PNG DNS Forum held from 6 to 10 May, 2024 in Port Moresby, Papua New Guinea.
Bridging the Digital Gap Brad Spiegel Macon, GA Initiative.pptxBrad Spiegel Macon GA
Brad Spiegel Macon GA’s journey exemplifies the profound impact that one individual can have on their community. Through his unwavering dedication to digital inclusion, he’s not only bridging the gap in Macon but also setting an example for others to follow.
Understanding User Behavior with Google Analytics.pdfSEO Article Boost
Unlocking the full potential of Google Analytics is crucial for understanding and optimizing your website’s performance. This guide dives deep into the essential aspects of Google Analytics, from analyzing traffic sources to understanding user demographics and tracking user engagement.
Traffic Sources Analysis:
Discover where your website traffic originates. By examining the Acquisition section, you can identify whether visitors come from organic search, paid campaigns, direct visits, social media, or referral links. This knowledge helps in refining marketing strategies and optimizing resource allocation.
User Demographics Insights:
Gain a comprehensive view of your audience by exploring demographic data in the Audience section. Understand age, gender, and interests to tailor your marketing strategies effectively. Leverage this information to create personalized content and improve user engagement and conversion rates.
Tracking User Engagement:
Learn how to measure user interaction with your site through key metrics like bounce rate, average session duration, and pages per session. Enhance user experience by analyzing engagement metrics and implementing strategies to keep visitors engaged.
Conversion Rate Optimization:
Understand the importance of conversion rates and how to track them using Google Analytics. Set up Goals, analyze conversion funnels, segment your audience, and employ A/B testing to optimize your website for higher conversions. Utilize ecommerce tracking and multi-channel funnels for a detailed view of your sales performance and marketing channel contributions.
Custom Reports and Dashboards:
Create custom reports and dashboards to visualize and interpret data relevant to your business goals. Use advanced filters, segments, and visualization options to gain deeper insights. Incorporate custom dimensions and metrics for tailored data analysis. Integrate external data sources to enrich your analytics and make well-informed decisions.
This guide is designed to help you harness the power of Google Analytics for making data-driven decisions that enhance website performance and achieve your digital marketing objectives. Whether you are looking to improve SEO, refine your social media strategy, or boost conversion rates, understanding and utilizing Google Analytics is essential for your success.
Instagram has become one of the most popular social media platforms, allowing people to share photos, videos, and stories with their followers. Sometimes, though, you might want to view someone's story without them knowing.
Discover the benefits of outsourcing SEO to Indiadavidjhones387
"Discover the benefits of outsourcing SEO to India! From cost-effective services and expert professionals to round-the-clock work advantages, learn how your business can achieve digital success with Indian SEO solutions.
Ready to Unlock the Power of Blockchain!Toptal Tech
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2. OBJECTIVES:
To discuss FTP and two connections used in this protocol:
control connection and data connection.
To discuss six classes of commands sent by the client to establish
communication with the server.
To explain three types of file transfer transferred by FTP.
To show some user-friendly commands used by some FTP
interfaces.
To discuss anonymous FTP and its application.
To discuss how file transfer can be done using a secure channel.
To discuss TFTP as a simple file transfer protocol without the
complexities and sophistication of FTP.
2
TCP/IP Protocol Suite
3. OBJECTIVES (continued):
To discuss five types of TFTP messages and their applications.
To discuss the sorcerer’s apprentice bug related to TFTP’s flow-
and error-control mechanisms.
To show how TFTP can be used in conjunction with DHCP to
initialize devices by downloading configuration files.
3
TCP/IP Protocol Suite
5. 21-1 FTP
File Transfer Protocol (FTP) is the standard mechanism
provided by TCP/IP for copying a file from one host to
another. Although transferring files from one system to
another seems simple and straightforward, some
problems must be dealt with first. For example, two
systems may use different file name conventions. Two
systems may have different ways to represent text and
data. Two systems may have different directory
structures. All of these problems have been solved by
FTP in a very simple and elegant approach.
5
TCP/IP Protocol Suite
6. Topics Discussed in the Section
Connections
Communication
Command Processing
File Transfer
Anonymous FTP
Security for FTP
The sftp Program
6
TCP/IP Protocol Suite
7. FTP uses the services of TCP.
It needs two TCP connections. The well-
known port 21 is used for the control
connection and the well-known
port 20 for the data connection.
Note
7
TCP/IP Protocol Suite
23. Figure 21.8 shows an example of using FTP for retrieving a list of
items in a directory.
Example 21.1
23
TCP/IP Protocol Suite
24. Figure 21.8 Example 21.1
220 (Service ready)
USER forouzan
LIST /usr/user/forouzan/reports
PASS xxxxxx
125 (Data connection OK)
331 (User name OK. Password?)
PORT 8888
150 (Data connection opens shortly)
230 (User login OK)
1
2
3
4
5
6
7
8
9
List of files or directories
List of files or directories
10
11
QUIT
226 (Closing data connection)
221 (Service closing)
12
13
14
DATA
TRANSFER
24
TCP/IP Protocol Suite
25. The following shows an actual FTP session that parallels Example
21.1. The colored lines show the responses from the server control
connection; the black lines show the commands sent by the client.
The lines in white with black background show data transfer.
Example 21.2
25
TCP/IP Protocol Suite
26. Figure 21.9 shows an example of how an image (binary) file is
stored.
Example 21.3
26
TCP/IP Protocol Suite
27. Figure 21.9 Example 21.3
220 (Service ready)
USER forouzan
TYPE EBCDIC
STRU R
STOR/usr/user/forouzan/reports/file1
PASS xxxxxx
200 (OK)
200 (OK)
250 (OK)
331 (User name OK. Password?)
PORT 1267
150 (Data connection opens shortly)
230 (User login OK)
1
2
3
4
5
6
7
8
9
10
11
12
13
DATA
TRANSFER
Records of file ..........
Records of file ..........
15
14
QUIT
226 (Closing data connection)
221 (Service closing)
16
17
18
27
TCP/IP Protocol Suite
28. We show an example of anonymous FTP. We assume that some
public data are available at internic.net.
Example 21.4
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29. 21-2 TFTP
There are occasions when we need to simply copy a
file without the need for all of the features of the FTP
protocol. For example, when a diskless workstation or a
router is booted, we need to download the bootstrap
and configuration files. Here we do not need all of the
sophistication provided in FTP. We just need a protocol
that quickly copies the files.
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30. Topics Discussed in the Section
Messages
Connection
Data Transfer
UDP Ports
TFTP Example
TFTP Options
Security
Applications
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31. TFTP uses the services of UDP on the
well-known port 69.
Note
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45. OBJECTIVES:
To discuss the architecture of WWW and describe the concepts
of hypertext and hypermedia.
To describe Web clients and Web servers and their components.
To define URL as a tool to identify a Web server.
To introduce three different Web documents: static document,
dynamic document, and active document.
To discuss HTTP and its transactions.
To define and list the fields in a request message.
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46. OBJECTIVES (continued):
To define non-persistent and persistent connections in HTTP.
To introduce cookies and their applications in HTTP.
To discuss Web caching, its application, and the method used to
update the cache.
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48. 22-1 ARCHITECTURE
The WWW today is a distributed client-server service,
in which a client using a browser can access a service
using a server. However, the service provided is
distributed over many locations called sites. Each site
holds one or more documents, referred to as Web
pages. Each Web page, however, can contain some links
to other Web pages in the same or other sites. In other
words, a Web page can be simple or composite.
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49. Topics Discussed in the Section
Hypertext and Hypermedia
Web Client (Browser)
Web Server
Uniform Resource Locator (URL)
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50. Assume we need to retrieve a Web page that contains the
biography of a famous character with some pictures, which are
embedded in the page itself. Since the pictures are not stored as
separate files, the whole document is a simple Web page. It can be
retrieved using one single request/ response transaction, as shown
in Figure 22.1.
Example 22.1
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52. Now assume we need to retrieve a scientific document that
contains one reference to another text file and one reference to a
large image. Figure 22.2 shows the situation. The main document
and the image are stored in two separate files in the same site (file
A and file B); the referenced text file is stored in another site (file
C). Since we are dealing with three different files, we need three
transactions if we want to see the whole document. The first
transaction (request/response) retrieves a copy of the main
document (file A), which has a reference (pointer) to the second
and the third files.
Example 22.2
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54. A very important point we need to remember is that file A, file B,
and file C in Example 22.2 are independent Web pages, each with
independent names and addresses. Although references to file B or
C are included in file A, it does not mean that each of these files
cannot be retrieved independently. A second user can retrieve file
B with one transaction. A third user can retrieve file C with one
transaction.
Example 22.3
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57. 22-2 WEB DOCUMENTS
The documents in the WWW can be grouped into three
broad categories: static, dynamic, and active. The
category is based on the time the contents of the
document are determined.
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58. Topics Discussed in the Section
Static Documents
Dynamic Documents
Active Documents
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60. HTML, XML, XSL, and XHTML are
discussed in Appendix E.
Note
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61. Figure 22.6 Dynamic document using CGI
Request
1
Dynamic document
2
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62. Figure 22.7 Dynamic document using server-site script
Request
1
Dynamic document
2
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63. Dynamic documents are sometimes
referred to as server-site dynamic
documents.
Note
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64. Figure 22.8 Active document using Java applet
Request
1
Result
Run the applet
to get the result
Active document
2
Applet
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65. Figure 22.9 Active document using client-site script
Request
1
Run the JavaScript
(JS) to get the result
Result
2
JavaScript
JS
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66. Active documents are sometimes
referred to as client-site dynamic
documents.
Note
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67. 22-3 HTTP
The Hypertext Transfer Protocol (HTTP) is a protocol
used mainly to access data on the World Wide Web.
HTTP functions like a combination of FTP (Chapter 21)
and SMTP (Chapter 23). It is similar to FTP because it
transfers files and uses the services of TCP. However,
it is much simpler than FTP because it uses only one
TCP connection. There is no separate control
connection; only data are transferred between the
client and the server.
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68. Topics Discussed in the Section
HTTP Transaction
Conditional Request
Persistence
Cookies
Web Caching: Proxy Server
HTTP Security
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69. HTTP uses the services of TCP on well-
known port 80.
Note
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70. Figure 22.10 HTTP transaction
1
Request message
Request line
Headers
Body
A blank line
2
Response message
Status line
Headers
Body
A blank line
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77. This example retrieves a document (see Figure 22.13). We use the
GET method to retrieve an image with the path /usr/bin/image1.
The request line shows the method (GET), the URL, and the HTTP
version (1.1). The header has two lines that show that the client
can accept images in the GIF or JPEG format. The request does
not have a body. The response message contains the status line
and four lines of header. The header lines define the date, server,
MIME version, and length of the document. The body of the
document follows the header.
Example 22.4
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79. In this example, the client wants to send data to the server. We
use the POST method. The request line shows the method
(POST), URL, and HTTP version (1.1). There are four lines of
headers. The request body contains the input information. The
response message contains the status line and four lines of
headers. The created document, which is a CGI document, is
included as the body (see Figure 22.14).
Example 22.5
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81. HTTP uses ASCII characters. The following shows how a client can
directly connect to a server using TELNET, which logs into port 80.
Example 22.6
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82. The following shows how a client imposes the modification data
and time condition on a request.
Example 22.7
The status line in the responds shows the file is not modified after
the defined point of time. The body of the response message is
also empty.
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83. Figure 22.15 shows an example of a nonpersistent connection. The
client needs to access a file that contains two links to images. The
text file and images are located on the same server.
Example 22.8
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88. Figure 22.17 shows a scenario in which an electronic store can
benefit from the use of cookies. Assume a shopper wants to buy a
toy from an electronic store named BestToys. The shopper
browser (client) sends a request to the BestToys server.
Example 22.10
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89. Figure 22.17 Example 22.10
A customer file is
created with ID: 12343
Request
GET BestToys.com HTTP/1.1
1
Response
HTTP/1.1 200 OK
Set-Cookie: 12343
Page Representing the Toys
2
A vendor file is created
with cookie: 12343
Update
3
Request
GET image HTTP/1.1
Response
Cookie: 12343
Cookie
4
HTTP/1.1 200 OK
Page Representing the price
Update
5
Request
GET image HTTP/1.1
Cookie: 12343
Information about the payment
Cookie
6
Response
HTTP/1.1 200 OK
Order confirmation
Update
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91. OBJECTIVES:
To explain the architecture of electronic mail using four
scenarios.
To explain the user agent (UA), services provided by it, and two
types of user agents.
To explain the mechanism of sending and receiving e-mails.
To introduce the role of a message transfer agent and Simple
Mail
Transfer Protocol (SMTP) as the formal protocol that handles
MTA.
To explain e-mail transfer phases.
To discuss two message access agents (MAAs): POP and IMAP.
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92. OBJECTIVES (continued):
To discuss MIME as a set of software functions that transforms
non-ASCII data to ASCII data and vice versa.
To discuss the idea of Web-based e-mail.
To explain the security of the e-mail system.
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93. Chapter
Outline
23.1 Architecture
23.2 User Agent
23.3 Message Transfer Agent
23.4 Message Access Agent
23.5 MIME
23.6 Web-Based Mail
23.7 Electronic Mail Security
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94. 23-1 ARCHITECTURE
To explain the architecture of e-mail, we give four
scenarios. We begin with the simplest situation and add
complexity as we proceed. The fourth scenario is the
most common in the exchange of e-mail.
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95. Topics Discussed in the Section
First Scenario
Second Scenario
Third Scenario
Fourth Scenario
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99. When the sender and the receiver of an
e-mail are on different mail servers,
we need two UAs and a pair of MTAs
(client and server).
Note
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101. When the sender is connected to the
mail server via a LAN or a WAN, we
need two UAs and two pairs of MTAs
(client and server).
Note
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103. When both sender and receiver are
connected to the mail server via a LAN
or a WAN, we need two UAs, two pairs of
MTAs (client and server), and a pair of
MAAs (client and server). This is the
most common situation today.
Note
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105. 23-2 USER AGENT
The first component of an electronic mail system is the
user agent (UA). It provides service to the user to
make the process of sending and receiving a message
easier.
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106. Topics Discussed in the Section
Services Provided by a User Agent
User Agent Types
Sending Mail
Receiving Mail
Addresses
Mailing List or Group List
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107. Some examples of command-driven
user agents are mail, pine, and elm.
Note
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108. Some examples of GUI-based user
agents are Eudora, Outlook,
And Netscape.
Note
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111. 23-3 MESSAGE TRANSFER AGENT
The actual mail transfer is done through message
transfer agents (MTAs). To send mail, a system must
have the client MTA, and to receive mail, a system must
have a server MTA. The formal protocol that defines the
MTA client and server in the Internet is called Simple
Mail Transfer Protocol (SMTP). As we said before, two
pairs of MTA client-server programs are used in the
most common situation (fourth scenario). Figure 23.8
shows the range of the SMTP protocol in this scenario.
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112. Topics Discussed in the Section
Commands and Responses
Mail Transfer Phases
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120. Let us see how we can directly use SMTP to send an e-mail and
simulate the commands and responses we described in this
section. We use TELNET to log into port 25 (the well-known port
for SMTP). We then use the commands directly to send an e-mail.
In this example, forouzanb@adelphia.net is sending an e-mail to
himself. The first few lines show TELNET trying to connect to the
adelphia mail server.
Example 23.1
After connection, we can type the SMTP commands and then
receive the responses as shown below. We have shown the
commands in black and the responses in color. Note that we have
added for clarification some comment lines, designated by the “=”
sign. These lines are not part of the e-mail procedure.
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122. 23-4 MESSAGE ACCESS AGENT
The first and the second stages of mail delivery use
SMTP. However, SMTP is not involved in the third
stage because SMTP is a push protocol; it pushes the
message from the client to the server. In other words,
the direction of the bulk data (messages) is from the
client to the server. On the other hand, the third stage
needs a pull protocol; the client must pull messages
from the server. The direction of the bulk data are from
the server to the client. The third stage uses a message
access agent.
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126. 23-5 MIME
Electronic mail has a simple structure. Its simplicity,
however, comes with a price. It can send messages only in
NVT 7-bit ASCII format. In other words, it has some
limitations. Multipurpose Internet Mail Extensions (MIME)
is a supplementary protocol that allows non-ASCII data to
be sent through e-mail. MIME transforms non-ASCII data
at the sender site to NVT ASCII data and delivers it to
the client MTA to be sent through the Internet. The
message at the receiving site is transformed back to the
original data.
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135. 23-6 WEB-BASED MAIL
E-mail is such a common application that some
websites today provide this service to anyone who
accesses the site. Three common sites are Hotmail,
Yahoo, and Google. The idea is very simple. Let us go
through two cases:
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136. Topics Discussed in the Section
Case I
Case II
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137. Figure 23.19 Web-based e-mail, case 1
1
2
3
4
HTTP
transactions
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138. Figure 23.20 Web-based e-mail, case 2
HTTP
transactions
HTTP
transactions
1 2 3
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139. 23-6 E-MAIL SECURITY
The protocol discussed in this chapter does not
provide any security provisions per se. However, e-mail
exchanges can be secured using two application-layer
securities designed in particular for e-mail systems.
Two of these protocols, Pretty Good Privacy (PGP)
and Secure MIME (SMIME) are discussed in Chapter 30
after we have discussed the basic network security.
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