Binarytech Digital Education Karta Allahabad ( Notes)

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1 is a service which allows us to send the message in electronic mode over the internet. It offers an efficient, inexpensive and real time mean of distributing information among people. Address Each user of is assigned a unique name for his account. This name is known as address. Different users can send and receive messages according to the address. is generally of the form username@domainname. For example, webmaster@tutorialspoint.com is an address where webmaster is username and tutorialspoint.com is domain name. The username and the domain name are separated (at) symbol. addresses are not case sensitive. Spaces are not allowed in address. Message Components message comprises of different components: Header, Greeting, Text, and Signature. Header The first five lines of an message is called header. The header part comprises of following fields: 1) From 2) Date 3) To 4) Subject 5) CC 6) BCC FROM The From field indicates the sender s address i.e. who sent the . DATE The Date field indicates the date when the was sent. TO The To field indicates the recipient s address i.e. to whom the is sent. SUBJECT The Subject field indicates the purpose of . It should be precise and to the point. CC CC stands for Carbon copy. It includes those recipient addresses whom we want to keep informed but not exactly the intended recipient. BCC BCC stands for Black Carbon Copy. It is used when we do not want one or more of the recipients to know that someone else was copied on the message. GREETING Greeting is the opening of the actual message. Eg. Hi Sir or Hi Guys etc. TEXT It represents the actual content of the message. SIGNATURE This is the final part of an message. It includes Name of Sender, Address, and Contact Number. This is the part which automatically include in the mail which we sent. 1 P a g e

2 Advantages has proved to be powerful and reliable medium of commmunication. Here are the benefits of E- mail: Reliable Convenience Speed Inexpensive Printable Global Generality Reliable Many of the mail systems notify the sender if message was undeliverable. Convenience There is no requirement of stationary and stamps. One does not have to go to post office. But all these things are not required for sending or receiving an mail. Speed is very fast. However, the speed also depends upon the underlying network. Inexpensive The cost of sending is very low. Printable It is easy to obtain a hardcopy of an . Also an electronic copy of an can also be saved for records. Global can be sent and received by a person sitting across the globe. Generality It is also possible to send graphics, programs and sounds with an . Disadvantages Apart from several benefits of , there also exists some disadvantages as discussed below: Forgery Overload Misdirection Junk No response Forgery doesn t prevent from forgery, that is, someone impersonating the sender, since sender is usually not authenticated in any way. Overload Convenience of may result in a flood of mail. Misdirection It is possible that you may send to an unintended recipient. Junk Junk s are undesirable and inappropriate s. Junk s are sometimes referred to as spam. No Response It may be frustrating when the recipient does not read the and respond on a regular basis. 2 P a g e

3 IMAP (Internet Message Access Protocol) IMAP (Internet Message Access Protocol) is a standard protocol that stores messages on a mail server, but allows the end user to view and manipulate the messages as though they were stored locally on the end user's computing device(s). This allows users to organize messages into folders, have multiple client applications know which messages have been read, flag messages for urgency or followup and save draft messages on the server. IMAP can be contrasted with another client/server protocol, Post Office Protocol 3 (POP3). With POP3, mail is saved for the end user in a single mailbox on the server and moved to the end user's device when the mail client opens. While POP3 can be thought of as a "store-and-forward" service, IMAP can be thought of as a remote file server. Most implementations of IMAP support multiple logins; this allows the end user to simultaneously connect to the server with different devices. For example, the end user could connect to the mail server with his Outlook iphone app and his Outlook desktop client at the same time. The details for how to handle multiple connections are not specified by the protocol but are instead left to the developers of the mail client. Even though IMAP has an authentication mechanism, the authentication process can easily be circumvented by anyone who knows how to steal a password by using a protocol analyser because the client s username and password are transmitted as clear text. In an Exchange Server environment, administrators can work around this security flaw by using Secure Sockets Layer (SSL) encryption for IMAP. Key Points: 1) IMAP allows the client program to manipulate the message on the server without downloading them on the local computer. 2) The is hold and maintained by the remote server. 3) It enables us to take any action such as downloading, delete the mail without reading the mail.it enables us to create, manipulate and delete remote message folders called mail boxes. 4) IMAP enables the users to search the s. 5) It allows concurrent access to multiple mailboxes on multiple mail servers. SMTP SMTP stands for Simple Mail Transfer Protocol. It was first proposed in It is a standard protocol used for sending efficiently and reliably over the internet. Key Points: 1) SMTP is application level protocol. 2) SMTP is connection oriented protocol. 3) SMTP is text based protocol. 4) It handles exchange of messages between servers over TCP/IP network. 5) Apart from transferring , SMPT also provides notification regarding incoming mail. 6) When you send , your client sends it to your server which further contacts the recipient mail server using SMTP client. 3 P a g e

4 7) These SMTP commands specify the sender s and receiver s address, along with the message to be send. 8) The exchange of commands between servers is carried out without intervention of any user. 9) In case, message cannot be delivered, an error report is sent to the sender which makes SMTP a reliable protocol. POP3 Post Office Protocol version 3 (POP3) is a standard mail protocol used to receive s from a remote server to a local client. POP3 allows you to download messages on your local computer and read them even when you are offline. Note, that when you use POP3 to connect to your account, messages are downloaded locally and removed from the server. This means that if you access your account from multiple locations that may not be the best option for you. On the other hand, if you use POP3, your messages are stored on your local computer, which reduces the space your account uses on your web server. By default, the POP3 protocol works on two ports: Port this is the default POP3 non-encrypted port Port this is the port you need to use if you want to connect using POP3 securely The Differences between POP and IMAP Both POP (Post Office Protocol) and IMAP (Internet Message access protocol) allow people to get access to their from a remote server; however, that is where most similarities end. POP simply downloads to your computer, and usually (but not always) deletes the from the remote server. The problems arise if you have more than one device where you read your mail (desktop, laptop, tablet or phone). Here's why it's bad: You have to delete or file the same on every device Logging into each device, you will see lots of unread s with no indication of which you deleted, read, flagged or filed Any folders you created and organize on one device won't be replicated on the other devices IMAP allows users to store their on remote servers. This two-way protocol also allows the user to synchronize their among multiple devices, which is extremely important today, when most people have at least two devices - their laptop and smartphone. Hacking hacking can be done in any of the following ways: 1) Spam 2) Virus 3) Phishing Spam spamming is an act of sending Unsolicited Bulk s (UBI) which one has not asked for. spams are the junk mails sent by commercial companies as an advertisement of their products and services. Virus Some s may incorporate with files containing malicious script which when run on your computer may lead to destroy your important data. 4 P a g e

5 Phishing phishing is an activity of sending s to a user claiming to be a legitimate enterprise. Its main purpose is to steal sensitive information such as usernames, passwords, and credit card details. Such s contains link to websites that are infected with malware and direct the user to enter details at a fake website whose look and feels are same to legitimate one. Usenet (USEr NETwork) Like mailing lists Usenet is also a way of sharing information. It was started by Tom Truscott and Jim Ellis in Initially it was limited to two sites but today there are thousands of Usenet sites involving millions of people. Usenet is a kind of discussion group where people can share views on topic of their interest. The article posted to a newsgroup becomes available to all readers of the newsgroup. Newsgroup Classification There exist a number of newsgroups distributed all around the world. These are identified using a hierarchical naming system in which each newsgroup is assigned a unique name that consists of alphabetic strings separated by periods. The leftmost portion of the name represents the top-level category of the newsgroup followed by subtopic. The subtopic can further be subdivided and subdivided even further (if needed). 5 P a g e