Wednesday, December 3, 2014

CS 2302 Computer Networks Unit 5

1. Discuss the basic model of FTP. (NOV/DEC 2007 & MAY/JUNE  2009)
The client has three components: the user interface, the client control process, and the client data transfer process. The server has two components: the server control process and the server data transfer process. The control connection is made between the control processes. The data connection is made between the data transfer processes.
2.What is a digital signature?

Digital signature is a method to authenticate the sender of a message. It is similar to that of signing transactions documents when you do business with a bank. In network transactions, you can create an equivalent of an electronic or digital signature by the way you send data.
3. Define Cryptography
n  Cryptography refers to the science and art of transforming messages to make them secure and immune to attacks.
n  Original message before being transformed is called plaintext.
n  After the message is transformed, is called ciphertext.
n  An encryption algorithm transforms the plaintext to ciphertext; a decryption algorithm transforms the ciphertext back to plaintext.
n  The term cipher is used to refer to encryption and decryption algorithms.

4. What are the types of DNS Message
n  Two types of messages
                Query: header and question records
n  Response: Header, question records, answer records, authoritative records, and additional records.
5. What is TELNET PROTOCOL?
   A TELNET connection is a Transmission Control Protocol (TCP)    connection used to transmit data with interspersed TELNET control information.
 
   The TELNET Protocol is built upon three main ideas:  first, the    concept of a "Network Virtual Terminal"; second, the principle of    negotiated options; and third, a symmetric view of terminals and    processes.

6. What is PGP?
Pretty Good Privacy. A program using public key encryption popularly used with email
A high security RSA public-key encryption application for MS-DOS, Unix, VAX/VMS, and other computers. It was written by Philip R. Zimmermann  of Phil's Pretty Good(tm) Software and later augmented by a cast of thousands, especially including Hal Finney, Branko Lankester, and Peter Gutmann.

7. What is POP3?
POP3 (Post Office Protocol 3) is the most recent version of a standard protocol for receiving e-mail. POP3 is a client/server protocol in which e-mail is received and held for you by your Internet server. POP and IMAP deal with the receiving of e-mail and are not to be confused with the Simple Mail Transfer Protocol (SMTP), a protocol for transferring e-mail across the Internet.
   
8. What is IMAP.
IMAP (Internet Message Access Protocol) is a standard protocol for accessing e-mail from your local server. IMAP (the latest version is IMAP Version 4) is a client/server protocol in which e-mail is received and held for you by your Internet server.
IMAP can be thought of as a remote file server. POP3 can be thought of as a "store-and-forward" service.

9. What is SSH?
(Secure Shell) A security protocol for logging into a remote server. SSH provides an encrypted session for transferring files and executing server programs. Also serving as a secure client/server connection for applications such as database access and e-mail SSH supports a variety of authentication methods.

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