Network Applications (HTTP, Email, etc)

Write a difference between FTP and TFTP.

Write a short note on FTP Protocol.

• FTP stands for File Transfer Protocol.
• It is a standard network protocol used to transfer computer files from one host to another host over a TCP-based network, such as the Internet.
• It is based on a client-server architecture and uses separate control and data connections between the client and the server.
• It may run in active or passive mode which determines how the data connection is established.
• Data transfer is reliable in FTP. Reliability is the primary function of FTP to transfer files and allow the convenientuse of remote file storage capabilities.
• It is a client-server protocol that relies on two communications channels between client and server.

• FTP uses the Internet's TCP/IP protocol to enable data transfer.
• It works in the same way as HTTP for transferring a web page from a server to a user's browser and SMTP for transferring electronic mail across the Internet.
• It uses a client-server architecture.
• Users provide authentication using a sign-in protocol, usually a username and password, however some FTP servers may be configured to accept FTP logins where you don't need to identify yourself before accessing the files.
• FTP is secured with SSL/TLS.

• FTP is commonly used to download a file from a server using the internet or to upload a file to a server.
• It promotes sharing of files via remote computers with reliable and efficient data transfer.

Write a short note on MIME.

• MIME stands for Multi-Purpose Internet Mail Extensions.
• It is an extension of the original Internet e-mail protocol, which is used to exchange different kinds of data files on the Internet such as, audio, video, image, application program etc.
• All the manually composed and automated emails are transmitted through SMTP in MIME format.
• It encodes the binary file and send them.
• MIME is extensible because it defines a method to register new content types and other MIME attribute values.

• MIME supports for multiple attachments in a single message.
• It supports the non-ASCII characters.
• It is used for layout, font and color which are categorized as rich text.
• It is used for attachments which contain executables, audio and video files etc.
• It supports for unlimited message length.

Write a short note on Mail gateways.

• Mail gateway is a machine that handles connections between networks that run different communications protocol.
• It is the simplest mail gateway that connects two network which use a common protocol.
• It handles the mail with an address for which 'sendmail' cannot find a recipient in your domain.
• It is a mail gateway exists, 'sendmail' uses it for sending and receiving mail outside the domain.
• A computer server acting as a gateway node and often also acts as a proxy server and a firewall server.
• A gateway is often associated with both a router, which knows where to direct a given packet of data that arrives at the gateway.
• If you have to set up a mail gateway, you should find a gateway configuration file that is close to what you need and modify it to conform to your situation.
• If you have a machine that provides connections to the Internet, you can configure that machine as the mail gateway. Carefully consider your site's security needs before you configure a mail gateway. You might need to create a firewall gateway between your corporate network and the outside world, and set up that gateway as the mail gateway.

Write a short note on SMTP.

• SMTP stands for Simple Mail Transfer Protocol.
• It is the standard protocol for electronic mail (email) transmission.
• It is a non-encrypted port, by default it uses port 25.
• There are some other ports that are also used in SMTP such as Port 465, which is used to send messages securely using SMTP.
• It is a TCP/IP protocol used in sending and receiving e-mail.



• On Unix-based system, 'sendmail' is the most widely-used SMTP server for e-mail.
• It is usually uses one of two other protocols, POP3 or IMAP, that user save messages in a server mailbox and download them periodically from the server.
• The user uses SMTP for sending e-mail and either POP3 or IAMP for receiving e-mail.
• A commercial package, 'sendmail' includes a POP3 server.

Write a short note on NTP.

• NTP stands for Network Time Protocol.
• It is a networking protocol used for clock synchronization of computers to some time reference.
• It is a protocol designed to synchronize the clocks of computers over a network.
• It is intended to synchronize all participating computers to within a few milliseconds of Coordinated Universal Time.
• NTP uses a modified version of Marzullo's algorithm to select accurate time servers.
• This protocol is designed to mitigate the effects of variable network latency.
• NTP is described in a client-server model.
• It can be used in peer-to-peer relationships where both peers consider the potential time source.
• It supplies a warning of any impeding leap second adjustment, but local time zones or daylight saving time is not transmitted the information.

• It is a fault-tolerant protocol.
• It is highly scalable.
• It can use past measurements to estimate the current time and error.
• It maintains the estimates for the accuracy of the local time.
• It can select best candidates to build its estimate of the current time.

Write a short note on SNMP.

• SNMP stands for Simple Network Management Protocol.
• It is an application-layer protocol.
• SNMP is defined by the Internet Architecture Board (IAB) in RFC1157 for exchanging management information between network devices.
• The following diagram illustrates the four–layer model developed by Department of Defense (DoD).


• This protocol is a part of the TCP/IP (Transmission Control Protocol/ Internet Protocol) suite.
• The SNMP messages are wrapped as User Datagram Protocol (UDP) and intern wrapped and transmitted in the Internet Protocol.
• It is one of the widely accepted protocols to manage and monitor network elements.