1) Email is sent using SMTP and travels through various servers until it reaches the destination mail server.
2) The email is then stored on the destination mail server and retrieved by the recipient using either POP3 or IMAP when they access their email.
3) POP3 downloads emails to the local machine while IMAP stores emails on the server and allows remote access.
The document discusses the architecture and components of email systems. It describes how early email systems required both the sender and recipient to be online simultaneously, while present systems use a store-and-forward model where neither need be online. It outlines the key components of email, including user agents for composing and reading messages, and message transfer agents for moving messages between systems. Common protocols like SMTP, POP, and IMAP are discussed for sending, receiving, and accessing emails.
This document provides information about Introduction to Computers Group 7. It lists the group members and provides brief descriptions of email, how email works, parts of an email address, protocols used for email (SMTP, POP3, IMAP), and what an ATM is along with its basic structure and how ATM transactions work. It also discusses chat/instant messaging explaining how it connects users and how messages are sent and received in real-time. Finally, it touches on video conferencing software Skype, explaining how it allows users to make voice and video calls over the internet using Voice over Internet Protocol (VoIP).
The Fundamental of Electronic Mail (E-mail)Vishal Kumar
This document contain the complete information about the Electronic mail. you will learn the basic structure and flow of email message, the Header and response codes, etc.
The document discusses the history and architecture of email. It describes how email works through a system of user agents, message transfer agents, and message access agents. Users compose messages with a user agent, which are then transferred between mail servers by message transfer agents using SMTP and retrieved by recipients with a message access agent. The document outlines the typical components of an email message and addresses, as well as the different scenarios for how email can be exchanged between users on the same or different systems.
E-mail uses a client-server model with three main components - the user agent (UA), the message transfer agent (SMTP), and the message access agent (POP3/IMAP). A basic e-mail message involves the UA composing a message on the client, the MTA transferring it to the server using SMTP protocols, and the MAA retrieving it from the server to the recipient's UA using POP3 or IMAP protocols. MIME extensions allow non-text data like images and files to be sent as attachments by encoding them into ASCII format during transfer.
Electronic mail, commonly known as email, allows users to transmit messages over the Internet. It uses Simple Mail Transfer Protocol (SMTP) to send messages between servers and uses either POP3 or IMAP for users to access their messages. SMTP focuses on reliably transferring messages between machines while POP3 and IMAP specify how users can retrieve and manage messages stored on the mail server. When sending an email, the sender's mail transfer agent adds a "received" header to the message to track its path through intermediate servers to the destination mail transfer agent. While convenient, SMTP is not secure and allows for spoofing, but techniques like SPF help validate authentic senders. Mail servers can also selectively reject traffic for policy or technical reasons.
This document discusses electronic mail representation and transfer. It describes the user agent, which prepares messages and stores them in mailboxes. Message transfer agents like SMTP transfer messages between systems using commands and responses. POP3 and IMAP are message access agents that allow users to retrieve messages stored on mail servers through protocols like POP3 or IMAP. MIME extensions allow non-text content like images and files to be sent via email.
1) Email is sent using SMTP and travels through various servers until it reaches the destination mail server.
2) The email is then stored on the destination mail server and retrieved by the recipient using either POP3 or IMAP when they access their email.
3) POP3 downloads emails to the local machine while IMAP stores emails on the server and allows remote access.
The document discusses the architecture and components of email systems. It describes how early email systems required both the sender and recipient to be online simultaneously, while present systems use a store-and-forward model where neither need be online. It outlines the key components of email, including user agents for composing and reading messages, and message transfer agents for moving messages between systems. Common protocols like SMTP, POP, and IMAP are discussed for sending, receiving, and accessing emails.
This document provides information about Introduction to Computers Group 7. It lists the group members and provides brief descriptions of email, how email works, parts of an email address, protocols used for email (SMTP, POP3, IMAP), and what an ATM is along with its basic structure and how ATM transactions work. It also discusses chat/instant messaging explaining how it connects users and how messages are sent and received in real-time. Finally, it touches on video conferencing software Skype, explaining how it allows users to make voice and video calls over the internet using Voice over Internet Protocol (VoIP).
The Fundamental of Electronic Mail (E-mail)Vishal Kumar
This document contain the complete information about the Electronic mail. you will learn the basic structure and flow of email message, the Header and response codes, etc.
The document discusses the history and architecture of email. It describes how email works through a system of user agents, message transfer agents, and message access agents. Users compose messages with a user agent, which are then transferred between mail servers by message transfer agents using SMTP and retrieved by recipients with a message access agent. The document outlines the typical components of an email message and addresses, as well as the different scenarios for how email can be exchanged between users on the same or different systems.
E-mail uses a client-server model with three main components - the user agent (UA), the message transfer agent (SMTP), and the message access agent (POP3/IMAP). A basic e-mail message involves the UA composing a message on the client, the MTA transferring it to the server using SMTP protocols, and the MAA retrieving it from the server to the recipient's UA using POP3 or IMAP protocols. MIME extensions allow non-text data like images and files to be sent as attachments by encoding them into ASCII format during transfer.
Electronic mail, commonly known as email, allows users to transmit messages over the Internet. It uses Simple Mail Transfer Protocol (SMTP) to send messages between servers and uses either POP3 or IMAP for users to access their messages. SMTP focuses on reliably transferring messages between machines while POP3 and IMAP specify how users can retrieve and manage messages stored on the mail server. When sending an email, the sender's mail transfer agent adds a "received" header to the message to track its path through intermediate servers to the destination mail transfer agent. While convenient, SMTP is not secure and allows for spoofing, but techniques like SPF help validate authentic senders. Mail servers can also selectively reject traffic for policy or technical reasons.
This document discusses electronic mail representation and transfer. It describes the user agent, which prepares messages and stores them in mailboxes. Message transfer agents like SMTP transfer messages between systems using commands and responses. POP3 and IMAP are message access agents that allow users to retrieve messages stored on mail servers through protocols like POP3 or IMAP. MIME extensions allow non-text content like images and files to be sent via email.
Electronic mail, or email, allows digital messages to be exchanged across computer networks like the Internet. Email systems rely on email servers to accept, forward, deliver, and store messages on behalf of users. An email consists of a header containing sender/recipient addresses and other metadata, and a message body. Standards like SMTP and MIME allow emails to be transmitted and support attachments. Key differences from physical mail include near-instant delivery, lower cost, and less physical effort required.
This document summarizes three major mail services - SMTP, POP3, and IMAP - and provides details on how each protocol works. SMTP is used for outbound email and uses port 25. POP3 and IMAP are for inbound email, with POP3 using port 110 and IMAP using port 143. The main difference between POP3 and IMAP is that POP3 assumes only one client can access the mailbox at a time, while IMAP allows simultaneous access from multiple clients.
SMTP is a protocol that handles the delivery of emails between servers. It works behind the scenes to move emails from the sender's computer to the recipient's inbox in a store-and-forward manner, passing through multiple servers along the way and briefly storing emails at each step. An SMTP relay service receives emails from a client and queues them for delivery to the final destination, either successfully delivering the email or returning a non-delivery report. It provides reputation-based filtering to help ensure only legitimate emails are delivered.
E-mail works by routing messages from server to server until it reaches the recipient's mail server. Messages are sent via SMTP servers called Mail Transport Agents (MTAs) and stored on the recipient's incoming mail server called a Mail Delivery Agent (MDA). Recipients then retrieve messages from the MDA using either POP3 or IMAP protocols. MTAs act like post offices that transport messages, while MDAs act like mailboxes that store messages until recipients access them. Retrieving mail requires a Mail User Agent like an email client or webmail interface.
Overview of Email protocols.
Electronic mail was one of the first applications of the fledgling Internet back in the 70ies of the last century. Mail represents basically an electronic equivalent of telegrams that can be sent without having a direct and simultaneous network connection with the recipient.
In email systems, a mail transfer agent (MTA) takes care of the message to be sent and repeatedly tries to deliver the message to the ultimate receiver until successful.
One of the first and still prevalent email protocols is SMTP (Simple Mail Transfer Protocol). It is a very simple protocol for sending electronic messages consisting of a header and a body between a sender and a recipient (relay agent or final mail transfer agent).
SMPT is not suited for receiving mail. Additional protocols like POP (Post Office Protocol) or the newer IMAP (Internet Mail Access Protocol) are needed to retrieve mail messages from a mail box.
SMPT was originally restricted to the ASCII character set so binary content or non-ASCII characters could not be used in mail messages. To overcome this limitation, MIME (Multipurpose Internet Mail Extensions) was devised to allow mail senders to encode non-ASCII content with special character encodings.
Electronic mail (email) evolved from traditional postal systems and telegraph communication. Ray Tomlinson is credited with inventing email in 1971 when he sent the first message containing the text "QWERTYUIOP" between two computers. Email works through an interaction between mail user agents, mail delivery agents, and mail transport agents that allow users to send and receive messages via protocols like SMTP, POP3, and IMAP running on port numbers 25, 110, and 143, respectively.
TCP/IP is the communication protocol for the Internet that defines rules for how computers communicate. It includes several protocols like TCP, UDP, IP, and ICMP. TCP/IP uses IP addresses and domain names to identify devices. It allows browsers to access servers, email programs to send and receive messages, and other Internet functions. TCP/IP is essential for electronic devices to connect and exchange data over the Internet.
E-Mail Header- A Forensic Key to Examine an E-MailIRJET Journal
This document summarizes an article about examining email headers for forensic purposes. It begins with an abstract discussing how email headers contain technical information about the path an email took, from sender to recipient, passing through multiple systems. It then discusses the structure of email headers, including the message header with information like date and subject, and envelope header with details added by mail servers. Finally, it describes how forensic analysts can examine email headers line by line to trace the routing of an email and identify the systems it passed through.
Electronic mail (email) has been in use for over three decades. The document provides an overview of the key components and processes that make up an email system. It discusses the architecture, which consists of user agents that allow people to read and send email, and message transfer agents that move messages between servers. Messages are sent between agents in a standard format defined by RFC 5322 and extended by MIME. The Simple Mail Transfer Protocol (SMTP) is used to transfer messages between agents over the internet.
A mail server is a central application that receives, stores, and sends email. It consists of a storage area to hold messages, user-defined rules to determine message routing and restrictions, a list of user accounts, and communication modules to transfer messages. A mail server receives messages from email clients or other mail servers, stores them temporarily, applies any relevant rules, and sends the messages to their intended recipients via its communication modules. A system administrator maintains the mail server and user accounts. Mail servers operate automatically without human intervention, processing messages as they are received.
Web Programming: Basics of Internet and Introduction to HTML5 and CSSKajal Singh
The document provides an overview of web programming. It discusses internet and the world wide web, including what the internet is, how it works using protocols like TCP/IP, and applications like email, telnet, FTP, e-commerce, video conferencing and e-business. It also covers HTML5 and how to format text and links using HTML tags. Finally, it discusses topics like advantages and disadvantages of e-commerce, components of video conferencing, and different types of e-business models.
Electronic mail, often abbreviated as email, e.mail or e-mail, is a method of exchanging digital messages. E-mail systems are based on a store-and-forward model in which e-mail computer server systems accept, forward, deliver and store messages on behalf of users, who only need to connect to the e-mail infrastructure, typically an e-mail server, with a network-enabled device (e.g., a personal computer) for the duration of message submission or retrieval. Originally, e-mail was always transmitted directly from one user's device to another's; nowadays this is rarely the case.ThesisScientist.com
Pop (post office protocol)e mail (electronic mail)MDSHABBIR12
Brief detail about pop3 and Electronic Mail. In this presentation, I describe the post office protocol and Electronic Mail.
1. History of Post Office Protocol.
2. Advantage and Disadvantage of postoffice protocol.
One of the most popular Internet services is electronic mail (e-mail).
At the beginning of the Internet era, the messages sent by electronic mail were short and consisted of text only.
Today, electronic mail is much more complex. It allows a message to include text, audio, and video.
It also allows one message to be sent to one or more recipients.
This document provides an overview of electronic mail (email) and its components. The three main components of email are:
1) User agents which allow users to compose, read, and manage emails. Examples include Outlook and Thunderbird.
2) Mail servers which store and transmit emails. Each user has a mailbox on a mail server.
3) SMTP (Simple Mail Transfer Protocol) which is used to transfer emails between mail servers over TCP port 25.
When a user composes an email, their user agent sends it to their mail server which stores it in the outgoing queue. The mail server then uses SMTP to transmit the email to the recipient's mail server, which stores it in the recipient's
Lesson 17 fundamental of internet (88 kb)IMRAN KHAN
The document discusses the history and fundamentals of the Internet. It begins by explaining how the US Defense Department funded ARPANET in 1969 to create a network that could withstand nuclear attacks. This led to the development of TCP/IP and connecting various networks, transforming ARPANET into today's Internet. The Internet provides key services like email, FTP, Telnet, and the World Wide Web. It allows for fast, global communication and access to information.
Email allows users to send electronic messages from one computer to another via the internet. It works on a client-server model where clients send and receive email through email servers connected over the internet. Email messages consist of a header containing sender, recipient, date and subject information, and a body containing the text and any attachments. Common email protocols include SMTP for message transfer between servers, and POP and IMAP for client access to messages on servers.
This document describes the development of an intranet messaging system. It includes code for starting the server, which creates server and client sockets to allow communication between clients and the server. The server displays received messages in a text area and sends acknowledgments. The coding chapter provides more details on implementing message sending functionality, including creating message objects, defining a GUI, and sending messages to the server.
This document discusses the structure and architecture of email. It begins with an introduction and history of email, then describes how an email is composed of a header and message body. It explains that emails are sent and received through a system of user agents, message transfer agents, and message access agents. User agents allow users to compose and read emails, while message transfer agents use SMTP to transfer emails across networks, and message access agents pull emails from servers using protocols like POP3 and IMAP.
E mail security using Certified Electronic Mail (CEM)Pankaj Bhambhani
The document discusses certified electronic mail (CEM) and its properties like non-repudiation, fairness, use of a trusted third party, and timeliness. It also summarizes the S/MIME protocol and proposes adding non-repudiation of receipt to S/MIME to improve its security. Finally, it outlines a key chain based CEM protocol that uses a transparent trusted third party and satisfies properties like non-repudiation of origin and receipt as well as fairness.
SSL/TLS provides encryption and authentication for secure internet communications. It originated from efforts by IETF, ANSI, and Netscape in the 1990s. SSL/TLS establishes a secure channel through a handshake to negotiate encryption keys before data transfer. SET builds on SSL/TLS to provide additional privacy, authentication, and integrity specifically for online credit card transactions through the use of digital signatures and certificates. It establishes separate encryption for payment and order information that is only revealed to authorized parties.
Electronic mail, or email, allows digital messages to be exchanged across computer networks like the Internet. Email systems rely on email servers to accept, forward, deliver, and store messages on behalf of users. An email consists of a header containing sender/recipient addresses and other metadata, and a message body. Standards like SMTP and MIME allow emails to be transmitted and support attachments. Key differences from physical mail include near-instant delivery, lower cost, and less physical effort required.
This document summarizes three major mail services - SMTP, POP3, and IMAP - and provides details on how each protocol works. SMTP is used for outbound email and uses port 25. POP3 and IMAP are for inbound email, with POP3 using port 110 and IMAP using port 143. The main difference between POP3 and IMAP is that POP3 assumes only one client can access the mailbox at a time, while IMAP allows simultaneous access from multiple clients.
SMTP is a protocol that handles the delivery of emails between servers. It works behind the scenes to move emails from the sender's computer to the recipient's inbox in a store-and-forward manner, passing through multiple servers along the way and briefly storing emails at each step. An SMTP relay service receives emails from a client and queues them for delivery to the final destination, either successfully delivering the email or returning a non-delivery report. It provides reputation-based filtering to help ensure only legitimate emails are delivered.
E-mail works by routing messages from server to server until it reaches the recipient's mail server. Messages are sent via SMTP servers called Mail Transport Agents (MTAs) and stored on the recipient's incoming mail server called a Mail Delivery Agent (MDA). Recipients then retrieve messages from the MDA using either POP3 or IMAP protocols. MTAs act like post offices that transport messages, while MDAs act like mailboxes that store messages until recipients access them. Retrieving mail requires a Mail User Agent like an email client or webmail interface.
Overview of Email protocols.
Electronic mail was one of the first applications of the fledgling Internet back in the 70ies of the last century. Mail represents basically an electronic equivalent of telegrams that can be sent without having a direct and simultaneous network connection with the recipient.
In email systems, a mail transfer agent (MTA) takes care of the message to be sent and repeatedly tries to deliver the message to the ultimate receiver until successful.
One of the first and still prevalent email protocols is SMTP (Simple Mail Transfer Protocol). It is a very simple protocol for sending electronic messages consisting of a header and a body between a sender and a recipient (relay agent or final mail transfer agent).
SMPT is not suited for receiving mail. Additional protocols like POP (Post Office Protocol) or the newer IMAP (Internet Mail Access Protocol) are needed to retrieve mail messages from a mail box.
SMPT was originally restricted to the ASCII character set so binary content or non-ASCII characters could not be used in mail messages. To overcome this limitation, MIME (Multipurpose Internet Mail Extensions) was devised to allow mail senders to encode non-ASCII content with special character encodings.
Electronic mail (email) evolved from traditional postal systems and telegraph communication. Ray Tomlinson is credited with inventing email in 1971 when he sent the first message containing the text "QWERTYUIOP" between two computers. Email works through an interaction between mail user agents, mail delivery agents, and mail transport agents that allow users to send and receive messages via protocols like SMTP, POP3, and IMAP running on port numbers 25, 110, and 143, respectively.
TCP/IP is the communication protocol for the Internet that defines rules for how computers communicate. It includes several protocols like TCP, UDP, IP, and ICMP. TCP/IP uses IP addresses and domain names to identify devices. It allows browsers to access servers, email programs to send and receive messages, and other Internet functions. TCP/IP is essential for electronic devices to connect and exchange data over the Internet.
E-Mail Header- A Forensic Key to Examine an E-MailIRJET Journal
This document summarizes an article about examining email headers for forensic purposes. It begins with an abstract discussing how email headers contain technical information about the path an email took, from sender to recipient, passing through multiple systems. It then discusses the structure of email headers, including the message header with information like date and subject, and envelope header with details added by mail servers. Finally, it describes how forensic analysts can examine email headers line by line to trace the routing of an email and identify the systems it passed through.
Electronic mail (email) has been in use for over three decades. The document provides an overview of the key components and processes that make up an email system. It discusses the architecture, which consists of user agents that allow people to read and send email, and message transfer agents that move messages between servers. Messages are sent between agents in a standard format defined by RFC 5322 and extended by MIME. The Simple Mail Transfer Protocol (SMTP) is used to transfer messages between agents over the internet.
A mail server is a central application that receives, stores, and sends email. It consists of a storage area to hold messages, user-defined rules to determine message routing and restrictions, a list of user accounts, and communication modules to transfer messages. A mail server receives messages from email clients or other mail servers, stores them temporarily, applies any relevant rules, and sends the messages to their intended recipients via its communication modules. A system administrator maintains the mail server and user accounts. Mail servers operate automatically without human intervention, processing messages as they are received.
Web Programming: Basics of Internet and Introduction to HTML5 and CSSKajal Singh
The document provides an overview of web programming. It discusses internet and the world wide web, including what the internet is, how it works using protocols like TCP/IP, and applications like email, telnet, FTP, e-commerce, video conferencing and e-business. It also covers HTML5 and how to format text and links using HTML tags. Finally, it discusses topics like advantages and disadvantages of e-commerce, components of video conferencing, and different types of e-business models.
Electronic mail, often abbreviated as email, e.mail or e-mail, is a method of exchanging digital messages. E-mail systems are based on a store-and-forward model in which e-mail computer server systems accept, forward, deliver and store messages on behalf of users, who only need to connect to the e-mail infrastructure, typically an e-mail server, with a network-enabled device (e.g., a personal computer) for the duration of message submission or retrieval. Originally, e-mail was always transmitted directly from one user's device to another's; nowadays this is rarely the case.ThesisScientist.com
Pop (post office protocol)e mail (electronic mail)MDSHABBIR12
Brief detail about pop3 and Electronic Mail. In this presentation, I describe the post office protocol and Electronic Mail.
1. History of Post Office Protocol.
2. Advantage and Disadvantage of postoffice protocol.
One of the most popular Internet services is electronic mail (e-mail).
At the beginning of the Internet era, the messages sent by electronic mail were short and consisted of text only.
Today, electronic mail is much more complex. It allows a message to include text, audio, and video.
It also allows one message to be sent to one or more recipients.
This document provides an overview of electronic mail (email) and its components. The three main components of email are:
1) User agents which allow users to compose, read, and manage emails. Examples include Outlook and Thunderbird.
2) Mail servers which store and transmit emails. Each user has a mailbox on a mail server.
3) SMTP (Simple Mail Transfer Protocol) which is used to transfer emails between mail servers over TCP port 25.
When a user composes an email, their user agent sends it to their mail server which stores it in the outgoing queue. The mail server then uses SMTP to transmit the email to the recipient's mail server, which stores it in the recipient's
Lesson 17 fundamental of internet (88 kb)IMRAN KHAN
The document discusses the history and fundamentals of the Internet. It begins by explaining how the US Defense Department funded ARPANET in 1969 to create a network that could withstand nuclear attacks. This led to the development of TCP/IP and connecting various networks, transforming ARPANET into today's Internet. The Internet provides key services like email, FTP, Telnet, and the World Wide Web. It allows for fast, global communication and access to information.
Email allows users to send electronic messages from one computer to another via the internet. It works on a client-server model where clients send and receive email through email servers connected over the internet. Email messages consist of a header containing sender, recipient, date and subject information, and a body containing the text and any attachments. Common email protocols include SMTP for message transfer between servers, and POP and IMAP for client access to messages on servers.
This document describes the development of an intranet messaging system. It includes code for starting the server, which creates server and client sockets to allow communication between clients and the server. The server displays received messages in a text area and sends acknowledgments. The coding chapter provides more details on implementing message sending functionality, including creating message objects, defining a GUI, and sending messages to the server.
This document discusses the structure and architecture of email. It begins with an introduction and history of email, then describes how an email is composed of a header and message body. It explains that emails are sent and received through a system of user agents, message transfer agents, and message access agents. User agents allow users to compose and read emails, while message transfer agents use SMTP to transfer emails across networks, and message access agents pull emails from servers using protocols like POP3 and IMAP.
E mail security using Certified Electronic Mail (CEM)Pankaj Bhambhani
The document discusses certified electronic mail (CEM) and its properties like non-repudiation, fairness, use of a trusted third party, and timeliness. It also summarizes the S/MIME protocol and proposes adding non-repudiation of receipt to S/MIME to improve its security. Finally, it outlines a key chain based CEM protocol that uses a transparent trusted third party and satisfies properties like non-repudiation of origin and receipt as well as fairness.
SSL/TLS provides encryption and authentication for secure internet communications. It originated from efforts by IETF, ANSI, and Netscape in the 1990s. SSL/TLS establishes a secure channel through a handshake to negotiate encryption keys before data transfer. SET builds on SSL/TLS to provide additional privacy, authentication, and integrity specifically for online credit card transactions through the use of digital signatures and certificates. It establishes separate encryption for payment and order information that is only revealed to authorized parties.
This document summarizes encryption techniques for securing electronic mail. It describes Pretty Good Privacy (PGP), a popular encryption software, and S/MIME, an emerging industry standard. PGP provides authentication, confidentiality, compression, and other services. It segments long messages for transmission. S/MIME uses public-key encryption and certificates to provide encrypted and signed messages and is compatible with SMTP email.
HTTPS: What, Why and How (SmashingConf Freiburg, Sep 2015)Guy Podjarny
When users use our sites, they put their faith in us. They trust we will keep their information from reaching others, believe we provided the information they see, and allow us to run (web) code on their devices. Using HTTPS to secure our conversations is a key part of maintaining this trust.
If that’s not motivation enough, the web’s giants are actively promoting HTTPS, requiring it for features such as HTTP2 & ServiceWorker, using it for search engine ranking and more. To make the most of the web, you need to use HTTPS.
This deck reviews what HTTPS is, discusses why you should prioritize using it, and cover some of the easiest (and most cost effective) steps to get started using HTTPS
This presentation is a basic insight into the Application Layer Protocols i.e. Http & Https. I was asked to do this as a part of an interview round in one of the networking company.
-Kudos
Harshad Taware
Bangalore ,India
This document discusses email security and encryption. It explains that email travels through unprotected networks and is exposed to attacks. It describes how email privacy aims to protect email from unauthorized access. Some remedies discussed are encrypting communication between servers using TLS and SASL authentication. The document also discusses using public-key cryptography for email encryption with tools like PGP and S/MIME, which can encrypt email content and add digital signatures for authentication. S/MIME is described as a security enhancement to the MIME email standard that provides encrypted and signed data functionality.
This document provides an overview of Secure Electronic Transaction (SET), which was created by Visa and Mastercard to securely facilitate online credit card transactions. SET uses public key cryptography including digital signatures and certificates to provide confidentiality, integrity, and authentication. It involves cardholders, merchants, issuers, acquirers, payment gateways, and a certification authority. The key steps in a SET transaction include the customer receiving an X.509 certificate, order and payment information being sent with dual signatures to link them, and the merchant requesting payment authorization from the payment gateway.
The document discusses computer networks and email. It describes how DNS works by converting domain names to IP addresses so humans can access websites using names instead of numbers. It then explains the basic architecture of email, including common email providers and protocols like SMTP, POP, and IMAP. SMTP is used to transfer messages between servers, while POP and IMAP deal with receiving and accessing emails from the server. The document also provides details on email message format, with the header containing sender/recipient info and the body containing the actual content.
SMTP (Simple Mail Transfer Protocol) is an Internet standard protocol for electronic mail transmission. It was first defined in 1982 and became widely used in the early 1980s as a complement to UUCP mail. SMTP uses a client-server model where the client initiates a connection and sends messages to the server, which then acknowledges receipt. It allows messages to be transferred between machines that are intermittently connected. Common SMTP commands include HELO, MAIL FROM, RCPT TO, DATA, QUIT, and RSET. SMTP can be secured using SSL/TLS to encrypt the communication channel. The latest developments include supporting real-time dynamic content in emails and internationalized email addresses encoded in UTF-8.
E-mail was invented in 1971 by Ray Tomlinson and allows computer users to exchange messages over a network. It consists of a header with information like the sender, recipient, date, and subject, and a body containing the message and any attachments. Email works on a client-server model, with clients like Outlook communicating with email servers using protocols like SMTP and POP3 over specific TCP/IP ports. While email enables quick communication, it can also spread viruses and users must be wary of scams. Overall, email remains one of the most effective ways to exchange information electronically.
SMTP is the standard protocol for sending emails between servers. Under SMTP, a client SMTP process opens a TCP connection to a remote server SMTP process and sends mail across the connection. The server listens on port 25 for connections. When a connection is made, the two processes execute a simple request-response dialogue defined by SMTP to transmit sender and recipient addresses and the email message itself. Mail is then forwarded to remote servers or delivered locally. POP3 and IMAP allow users to download stored mail from the local server.
A mail server is a computer that handles email delivery. It implements the client and server portions of SMTP to reliably transfer messages between servers using TCP on port 25. A mail server stores users' incoming emails in their mailboxes and queues outgoing messages to be sent. IMAP and POP3 are additional protocols that allow users to access their mailboxes to read and manage messages.
A mail server is a computer that handles email delivery. It implements the client and server portions of SMTP to reliably transfer messages between servers using TCP port 25. A mail server stores users' incoming emails in their mailboxes and queues outgoing messages to be sent. The major components of electronic mail systems are user agents for composing/reading mail, mail servers for message storage and transfer using SMTP, and protocols like POP3 and IMAP for users to access their mailboxes.
The document discusses network protocols and the OSI model. It explains that network protocols allow devices to communicate by establishing rules and data structures. It then describes the seven-layer OSI model and how network protocols operate at each layer to divide communication tasks. Some key application layer protocols discussed include DHCP for IP address management, DNS for domain name resolution, FTP for file transfer, HTTP for web browsing, IMAP/POP for email, SMTP for email transmission, Telnet for remote access, and SNMP for network management.
A deep introduction to Internet and internet services.
This ppt contains all the minor and major information about Internet from basic internet, www, concepts
Electronic mail, commonly known as email, allows digital messages to be exchanged between an author and recipients over computer networks like the Internet. Early email systems required both parties to be online simultaneously, but modern email uses a store-and-forward model where messages are sent to and stored on email servers until the recipient connects. An email consists of a message envelope containing sender/recipient addresses, a message header with fields like subject, and the message body. Originally only text, email has evolved to support attachments and non-ASCII character sets.
s.
MIME allows non-ASCII data like images, audio, and video to be sent through email by transforming
the data into ASCII format during transfer and then transforming it back at the receiving end. MIME
defines headers that are added to email messages to specify the encoding and content type. SMTP is
the underlying protocol that transfers email messages between servers using a series of commands
and responses to route messages from the sending to the receiving server.
te
This document discusses electronic mail (e-mail) and how it works. It describes the key components of an e-mail system including user agents, message transfer agents, and message access agents. It explains the store-and-forward model that modern e-mail uses to send and receive messages between users. It also outlines the main protocols used for e-mail - SMTP for sending messages between servers, and POP3 or IMAP for users to access their messages. IMAP is generally preferred as it allows accessing and organizing messages from multiple devices.
Modems are devices that convert digital data from computers into analog signals that can be transmitted over telephone lines, and vice versa. They allow computers to connect to networks over long distances using existing telephone infrastructure. Switches improve network performance over hubs by only forwarding data to the specific port of the intended recipient, reducing collisions. Routers connect multiple networks like a local area network to a wide area network such as the Internet.
This document provides information about courses and tutorials offered by WEIT Tutorials located in Thane, India. The tutorials cover various computer science and engineering courses including BSC, MCA, and engineering degrees. Contact information including the address, phone numbers, and social media links are provided to stay connected for updates and study notes.
Modems convert digital signals to analog signals for transmission over phone lines and vice versa. They are classified by connection type and transmission mode. Functions include data compression, error correction, and flow control. TCP/IP is the standard communication protocol for the Internet and networks. It has application, transport, internet, and link layers. The World Wide Web is a system of interlinked hypertext documents accessed via the Internet using browsers. It allows information sharing through URLs and hyperlinks.
This document discusses email security. It describes how email works using POP and SMTP servers and protocols. It outlines some security risks of receiving email like spam, phishing, and email-borne malware in attachments. It advises treating email like postcards that can be read by anyone, and not putting private information in unencrypted emails. It also warns about forged email headers that make emails appear to come from someone else.
The document provides an overview of electronic mail (email) including its definition, history, technical aspects, applications, and role in society. It discusses early host-based and LAN-based email systems from the 1960s and 1970s. Key components of email like SMTP, POP, and MIME protocols are explained. Common email applications include Microsoft Outlook, Outlook Express, and web-based email. The document also briefly discusses the impact and use of email in social communication and business.
The document discusses various application layer protocols used in networking. It covers:
1. The application layer is the top layer that interacts with users and user applications to initiate communication. It uses lower layer protocols to transfer data.
2. Common application layer protocols include HTTP, FTP, SMTP, POP3, IMAP, and DNS for tasks like web browsing, file transfer, and email.
3. Other applications discussed are peer-to-peer applications like BitTorrent and Skype, as well as socket programming which allows network applications to communicate using standard mechanisms.
Standard Client / Server Protocols: Worldwide- web and HTTP,FTP, Electronic mail, Telnet, Secured Shell, Domain name system. Application layer: DNS: Name space – domain name space – distribution of name space Electronic mail Architecture – FILE transfer: FTP WWW and HTTP: Architecture – web documents – HTTP Network Security: Introduction - definitions – two categories - symmetric key cryptography – traditional ciphers – asymmetric key cryptography
The document provides an overview of the internet and its evolution. It discusses how the internet started as a US government project called ARPANET in the 1960s. It later expanded to include universities, research labs, and other networks. By the late 1980s and 1990s, the NSFNET connected supercomputer centers and commercial internet services became available, allowing the general public access to the growing network of networks called the internet. The anatomy and basic components of the internet like clients, servers, protocols, and URL addressing are also summarized.
Similar to Email Security, The Essence of Secure E-mail (20)
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Haaga‐Helia University of Applied Sciences
E‐mail Security
When can I consider my e‐mail to be secure?
Ralph van der Pauw – a1000513
27/4/2010
2. Table of Contents
What is e‐mail? ........................................................................................................................................ 2
Simple Mail Transfer Protocol ......................................................................................................... 2
Post Office Protocol & Internet Message Access Protocol ............................................................. 2
Why should e‐mail be secure? ................................................................................................................ 4
How the internet works .................................................................................................................. 4
Common sense ................................................................................................................................ 5
Which threats exist in e‐mail? ................................................................................................................. 6
Trojans ............................................................................................................................................. 6
Viruses ............................................................................................................................................. 6
Worms ............................................................................................................................................. 7
How can these threats be eliminated? ................................................................................................... 9
Antivirus software ........................................................................................................................... 9
Think before you act ....................................................................................................................... 9
.
Which vulnerabilities exist in email? ..................................................................................................... 11
Privacy ........................................................................................................................................... 11
Spam & Phishing ............................................................................................................................ 12
How can these vulnerabilities be reduced? .......................................................................................... 13
Encryption (SSL, TLS & PGP) .......................................................................................................... 13
Spamfilters .................................................................................................................................... 13
.
Awareness ..................................................................................................................................... 14
Sources .................................................................................................................................................. 16
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11. Approach attachments with caution. If you are not expecting an attachment or you don’t
know from whom it is from, do not open it. Opening an attachment can trigger a malicious
code that wasn’t picked up by your anti‐virus software.
Do not forward chain e‐mail messages. Your e‐mail address is stored in the mail and you are
not able to keep track of who gets to see the e‐mail.
Always report suspicious e‐mail when received from a trusted address. If you receive
suspicious e‐mail from an address you know, contact the recipient about the suspicious e‐
mail to avoid possible spreading of a malicious code and to warn the client about what he or
she has sent.
As stated before it is not possible to eliminate a full 100% of the threats but by letting your (up‐to‐
date) anti‐virus application scan your e‐mail and by taking the above mentioned precautions, you
lower your risk level to the very minimum.
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15. Awareness
Awareness in using your e‐mail account might be just as important as installing technical precautions.
In corporations it is very important for the administrators to create this awareness among the
employees. Important precautions for e‐mail users are listed below.
Keep the number of e‐mail accounts to a minimum. It is wise to split personal and corporate
e‐mail over different accounts but to keep the number of accounts as low as possible.
Besides a personal and corporate account it is recommended to create a separate account
for less secure traffic, a so called spam‐account. This account can be used for internet forms
and unsecure communication (IT Security, 2008).
A more secure way of communication is the telephone. If your message can be sent by a
telephone call it is wise to choose this more secure and private option.
Spam traffic is usually cumulative. This means once you start to receive a lot of spam, the
amount will slowly increase. It is therefore smart to discard accounts which are receiving an
immense amount of spam (IT Security, 2007).
When accessing your e‐mail on a public computer, never use an e‐mail client but always use
the web‐interface of your e‐mail provider. When you are done with the session, close the
browser, log‐out and delete the cache, cookies, history and passwords so there are no traces
of your session left.
Avoid using the reply‐all or BCC option in sending e‐mails. This way you show your own and
other’s e‐mail addresses to a lot of users. Try using the CC option where other e‐mail
addresses are hidden to obtain privacy (IT Security, 2008).
Never send sensitive company information with your (unsecure) personal account, always
use your corporate account where your privacy can be protected by the company’s IT
department. If the information happens to be intercepted, you are less vulnerable in possible
law conflicts (IT Security, 2007).
Create regular backups of you e‐mail account. Important e‐mail might be stored in your mail
directories, always make sure these e‐mails are backed up on your computers. Also when
accessing your e‐mail on a mobile platform and using the POP protocol, make sure there is a
copy of the e‐mail on your server. A cellphone is easily lost and with that you would lose all
your e‐mails too.
An often used technique to obtain your e‐mail address is to send you newsletters with an
unsubscribe option. When you have clicked this option you will be linked to a webpage and
your e‐mail address will be stored. Don’t unsubscribe for these e‐mails unless you remember
subscribing to them (IT Security, 2007).
Phishing mails might slip through your spamfilter depending on the level of thoroughness
you set it to. Identify a phishing mail by looking for anything that implies the mail is not from
who it pretends to be. In the mail you will probably be asked to fill in personal information.
Most banks, web payments and auction sites use web‐forms for these matters so if you are
asked to mail your account details you can assume it is fake. If they give you a link to go to,
always hold your mouse cursor on the link to see where the address may lead you to. Check
carefully for spelling errors in the link which is a common trick to masquerade as a
trustworthy identity (Microsoft, 2010).
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