SMTP represents Simple Mail Transfer Protocol. SMTP is a set of interaction guidelines that allow the software to transmit electronic mail over the internet, referred to as Simple Mail Transfer Protocol.The main objective of SMTP is used to set up communication rules between servers. The servers have a way of recognizing themselves and announcing what kind of communication they are trying to perform. They also have a way of handling errors such as incorrect email address. For example, if the recipient address is wrong, then receiving a server reply with an error message of some kind.Working of SMTPSMTP is an ... Read More

E-mail is represented as the transmission of messages on the Internet. It is one of the most commonly used features over communications networks containing text, files, images, or other attachments.Format of E-mail− An e-mail includes three parts that are as follows−E-mail EnvelopeIn modern e-mail systems, there is a distinction made between the e-mail and its contents. An e-mail envelope contains the message, destination Address, Priority security level etc. The message transport agents use this envelope for routing.MessageThe actual message inside the envelope is made of two partsHeaderBodyThe header carries the control information while the Body contains the message contents. The ... Read More

One of the most famous network services is electronic mail (e-mail). The simple standard mechanism for electronic mail on the internet. The first email systems simply consisted of file transfer protocols.But some of the limitations of this system were as follows−Sending a message to a group of people was inconvenient.Messages did not have many internet structures. So, its computer processing was complex.The sender never knew if the message arrived or not.It was not easy to hand over one's email to someone else.The user interface was poorly integrated.It was impossible to create and send messages containing a text, drawing, facsimile and ... Read More

TFTP operation is very simple. The client sends a read or write request at the server's UDP port 69. The server accepts the request by sharing data messages in case of the read request and sending acknowledgement in the write request. In either case, the server chooses a UDP port for further dialogue and sends its first response to the client through the selected UDP port.Each data message has a fixed size of the data block (512 octets) and is individually acknowledged. The last data block containing EOF (End of File) or a data block containing less than 512 octets ... Read More

TFTP represents the Trivial File Transfer Protocol. Some applications do not need the full functionality of TCP, nor can they afford the complexity. TFTP supports an inexpensive structure that does not require complex interactions between the client and the server. TFTP confine operations to simple File Transfer and does not support authentications.The benefit of using TFTP is that it enables bootstrapping code to use the similar underlying TCP/IP protocols that the operating framework uses once it starts execution. Thus it is the possibility for a device to bootstrap from a server on another physical network.TFTP does not have a dependable ... Read More

When using File Transfer Protocol (FTP), the user implements some or all of the following operations −Connecting to a remote hostTo implement a file transfer, the user begins by logging into the remote host. Four commands are used.Open selects the remote host and sets up the login session.User recognizes the remote user ID.Pass authenticates the client.Site sends data to the foreign host that is used to provide services specific to that host.Navigating the directory structureAfter a client has been authenticated and logged on to the server, that client can navigate through the remote host's directory structure to locate the file ... Read More

The two types of Connections in FTP are as follows −Control ConnectionThere are two steps −The server issues a positive open on the well-known port 21 and waits for a client.The client uses an ephemeral port and issues an active open.The connection remains open during the whole process.Data ConnectionThe data connection facilitates the well-known port 20 at the server site. The following steps display how FTP creates a data connection.The user, not the server, issues a passive open using an ephemeral port.The client assigns this port number to the server using the PORT command.The server receives the port number and ... Read More

FTP represents File transfer protocol and it is a standard internet protocol supported by TCP/IP used for transmitting the files from one host to another. FTP needs TCP as a transport protocol to help the reliable end to end connections and executes two types of connections in managing data transfers.The FTP clients initiate the first connection, referred to as the control connection, to wellknown port 21 (the clients port is typically ephemeral). It is on this part that an FTP server listens for it and accepts new connections. The control connection is issued for all of the control commands a ... Read More

The functions of the presentation layer are as follows:It provides the users with a way to execute the session service primitives. For that, it uses the contexts, each consisting of some data types and their transfer syntaxes. When a session is established, the peer entities negotiate for one or more contexts. It can change these contexts as the session progresses.Once the negotiations have been agreed upon, each machine is free to represent the data structures internally in the most convenient form. It is known that it should express that it can be transmitted and understood by the remote peer entity ... Read More

The session layer services are provided by a functional unit set, which constitutes the session layer. The session layer can be understanding as a general-purpose tool kit out of which the user selects the tools to be used.The functions provided by the session layers are as follows:Session EstablishmentThe session layer’s primary function is to provide and establish connections between communicating users, known as sessions. It can transfer the data over these sessions in a reliable and orderly way.It can settle a session between two computers for communication, file transfer, remote login, or other purposes. It can establish Connection-oriented and connectionless ... Read More