Remote Login and File Transfer Protocols
- 1. COMPUTER APPLICATIONS CLASS X (Code 165) TOPIC: UNIT 1: Application Layer Protocols By HIMANSHU PATHAK
- 2. Contents • Introduction • Communication Protocol • Mail Protocol • File Transfer Protocol • Remote Login Protocol
- 3. Introduction • Application Layer uses protocols such as HTTP(S) on client side applications like browser. • The application layer is responsible for providing services to the user: – Accessing the www – Mail Services – File Transfer and Access – Remote Log-in
- 4. Communication Protocol: HTTP • HTTP stands for Hyper-Text Transfer Protocol. • HTTP is used mainly to access data on the world wide web. • HTTP provides standard rules for web browsers & servers to communicate. • An HTTP is a stateless protocol as each transaction is executed separately without having any knowledge of the previous transactions, which means that once the transaction is completed between the web browser and the server, the connection gets lost.
- 5. Communication Protocol: HTTPS • HTTPS stands for Hyper Text Transfer Protocol Secure. • It means all communications between your browser and the website are encrypted. • The use of HTTPS protocol is mainly required where we need to enter the bank account details. • The HTTPS protocol is mainly used where we require to enter the login credentials.
- 6. HTTP Vs. HTTPS HTTP HTTPS It is mainly used for those websites that provide information like blog writing. It is a secure protocol, so it is used for those websites that require to transmit the bank account details or credit card numbers. The HTTP transmits the data over port number 80. The HTTPS transmits the data over port number 443. The page loading speed is fast. The page loading speed is slow as compared to HTTP because of the additional feature that it supports, i.e., security. It is an application layer protocol. It is a transport layer protocol. It does not use SSL. It uses SSL that provides the encryption of the data.
- 7. Mail Protocol: SMTP • SMTP stands for Simple Mail Transfer Protocol. • SMTP is the standard mechanism for electronic mail in the internet. • The addressing system used by SMTP consists of two parts: Local part & Domain part • Local-part @ Domain-part • The main purpose of SMTP is used to set up communication rules between servers. • Most email clients allow for transfers of up to 25 MB.
- 8. Mail Protocol: POP3 • The POP protocol stands for Post Office Protocol. • POP3 is a client/server protocol in which e-mail is received and held for you by your Internet server. • Periodically, you (or your client e-mail receiver) check your mail-box on the server and download any mail, probably using POP3. • This standard protocol is built into most popular e-mail products, such as Eudora and Outlook Express.
- 9. SMTP Vs. POP3 SMTP POP3 SMTP is used to send the email POP is used to receive email SMTP acts as a MTA (Message Transfer Agent) POP3 is a MAA (Message Access Agent) The port number of SMTP is 25. The port number of POP3 is 110.
- 10. File Transfer Protocol: FTP • FTP stands for File Transfer Protocol. • FTP is an application layer protocol which moves files between local and remote file systems. • FTP establishes two connections between the client and the server: – One connection is used for data transfer (port 20). – And the other for control information (port 21). • The control connection is maintained during the entire FTP session while the data connection is opened and then closed for each file transferred.
- 11. File Transfer Protocol: SFTP • It stands for Secure File Transfer Protocol. • It builds on the File Transfer Protocol (FTP) and includes Secure Shell (SSH) security components. • Secure Shell is a cryptographic component of internet security. • SSH and SFTP were designed by the Internet Engineering Task Force (IETF) for greater web security. • SFTP transfers files security using SSH and encrypted FTP commands to avoid password sniffing and exposing sensitive information in plain text.
- 12. FTP Vs. SFTP FTP SFTP FTP uses 2 channels to transfer data SFTP usage 1 channel to transfer data It usually runs on port no-21 It runs on port no-22 It does not encrypt the data before sending It encrypted data before sending
- 13. SCP • SCP stands for Secure Copy Protocol. • Secure copy (SCP) is a file transfer protocol, which helps in transferring computer files securely from a local host to a remote host. • It works on the Secure Shell (SSH) protocol technique. • It doesn’t allow user to see and modify files on the server.
- 14. SFTP Vs. SCP SFTP SCP SFTP is slow SCP is fast SFTP has to ACK (acknowledge) every tiny packet SCP does not need to ACK (acknowledge) SCP is built purely for file transfers. Generally speaking, you can't generate directory listings (to view files within a directory), create directories, delete directories, delete files, and so on. SFTP, on the other hand, can readily perform these operations on its own.
- 15. Remote Login Protocol: Telnet • Telnet stands for Terminal Network. • It is a type of protocol that enables one computer to connect to local computer. • Computer which starts connection known as the local computer. Computer which is being connected to i.e. which accepts the connection known as remote computer. • During telnet operation whatever that is performing on the remote computer will be displayed by local computer.
- 16. Remote Login Protocol: SSH • The SSH protocol (also referred to as Secure Shell) is a method for secure remote login from one computer to another. • It provides several alternative options for strong authentication, and it protects the communications security and integrity with strong encryption. • It is a secure alternative to the non-protected login protocols (such as telnet) and insecure file transfer methods (such as FTP).
- 17. Telnet Vs. SSH TELNET SSH Telnet uses port 23 SSH runs on port 22 by default No privileges are provided for the user's authentication. SSH is a more secure protocol, so it uses public-key encryption for authentication. Suitable for private networks Suitable for public networks
- 18. Today we learn • Communication protocols • Remote login and file transfer protocols. • In the next class, we will see Web Services in detail. •Thanks