Remote Logging. Tanveer Brohi(14cs28)

Transcription

1 Remote Logging Tanveer Brohi(14cs28) 1

2 Contents Introduction TELNET SSH Advantages and Disadvantages Conclusion References 2

3 Introduction What is remote logging? Remote logging is the capability to access the files, documents and related software of one computer from another along the network 3

4 TELNET One of the original remote logging protocols is TELNET TELNET is an abbreviation for TErminal NETwork. It is the standard TCP/IP protocol for virtual terminal service as proposed by International Organization for Standard (ISO) TELNET enables the establishment of a connection to a remote system in such a way that the local terminal appears to be a terminal at the remote system 4

5 TELNET Although TELNET requires a logging name and password, it is vulnerable to hacking because it sends all data including the password in plaintext (not encrypted). A hacker can eavesdrop and obtain the logging name and password because of this security issue, the use of TELNET has diminished in favor of another protocol Secure Shell (SSH) 5

6 SSH- Secure Shell Tools used for Remote logging Remote logging is a software utility for Unix-like computer operating systems that allows users to log in on another host via a network Telnet: Telnet allows remote logging and can be used to access and run interactive applications on remote systems. You need to know the IP Address or the host name of the remote system and also have an account in order to access the remote system through telnet 6

7 SSH- Secure Shell Tools used for Remote logging Remote logging is a software utility for Unix-like computer operating systems that allows users to log in on another host via a network Telnet: Telnet allows remote logging and can be used to access and run interactive applications on remote systems. You need to know the IP Address or the host name of the remote system and also have an account in order to access the remote system through telnet 6

8 Remote Logging using SSH What is SSH? SSH is a network protocol that allows data to be exchanged using a secure channel between two networked devices. Uses of SSH. Access to the UNIX-like environment from a windows machine. Work from home with access to your file store. Copying files between your file store and another machine Read restricted web pages For executing command on a remote host 7

9 Advantages and Disadvantages Advantages: *Efficiency *Cost *Fast Disadvantages: *Lack of security 8

10 Conclusion Students may want to connect to their university computer lab from their home to access application programs for doing homework assignments or projects. One way to satisfy that demand and others is to create a client/server application program for each desired service. Programs such as file transfer programs (FTPs), (SMTP), and so on are currently available 9

11 References From book Data Communication and Networking by Forouzan file:///f:/my%20field%20networking/data%20communications%20& %20Networking,%204th%20Edition,\Behrouz%20A.%20Forouzan.pdf 10

12 Thank you 11

13 Electronic mail ( ) Mohammad YaQooB JuneJo 14CSE36

14 Contents Introduction Architecture 1 st Scenario 2 nd Scenario 3 rd Scenario 4 th Scenario Push v/s pull User agent & it s services Format of Address Bibliography

15 Introduction One of the most popular internet service. A network application in which mail messages are transmitted electronically between two end user (nodes) over various types of network using various network protocols.

16 More about at the beginning of the Internet era Short Messages were sent by e- mail. Consist of Text only today Much more complex Allows a message to include Text,Audio,Video. One message sent to one or more recipients.

17 Architecture To explain the architecture of , we give four scenarios. The 4 th scenario is the most common in exchange. Ø First Scenario Ø Second Scenario Ø Third Scenario Ø Fourth Scenario

18 First Scenario

19 Note: When the sender & the receiver of an are on the same system, we need only two user agents.

20 Second Scenario

21 Note: When the sender & the receiver of an are on different systems, we need two UAs & a pair of MTAs (client and server).

22 Third Scenario

23 Note: When the sender is connected to the mail server via a LAN or a WAN, we need two UAs and two pairs of MTAs (client and server).

24 Fourth Scenario

25 Push versus Pull When both sender and receiver are connected to the mail server via a LAN or a WAN, we need two UAs, two pairs of MTAs and a pair of MAAs. This is the most common situa.on today.

26 User agent The first component of an electronic mail system is the user agent (UA). It provides service to the user to make the process of sending and receiving a message easier.

27 Services of user agent

28 Format of

29 Address

30 Bibliography Ø h>p://ece626web.groups.et.byu.net/lectures/ch26.ppt Ø Data communicafon and Networks 4/e by Behrouz A. Forouzan

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32 FILE TRANSFER PRESENTED BY: 14CS38 IKHLAQUE AHMED DOMKI 2

33 CONTEXT WHAT IS FILE TRANSFER? FTP(FILE TRANSFER PROTOCOL) COMMUNICATION OVER CONTROL CONNECTION COMMUNICATION OVER DATA CONNECTION ANONYMOUS FTP 3

34 FILE TRANSFER Transferring files from one computer to another is one of the most common tasks expects from a network or internetworking environments. As a matter of fact, the greatest volume of data exchange in the internet today is due to file transfer. One popular is in file transferring is (FTP): FILE TRANSFER PROTOCOL 4

35 FTP Ftp is standard mechanism in provided by TCP/IP for copying a file from one host to another. Some problems : for example : two system may use different file name convention. Different ways to represents text and data s, different directory structure, All these problem have been solved by ftp in a very simple and elegant approach. FTP differs from client /server application in that its establishes two connection b/w the host.one use for data transfer other hand for control information (commands and response). 5

36 NOTE: FTP USES THE SERVICE OF TCP IT NEEDS TWO TCP COONECTION.THE WELL KNOWN PORT 21 IS USED FOR THE CONTROLCONNECTIONS AND THE WELL KNOWN PORT 20 FOR DATA CONNECTIONZ 6

37 Communication over control connection FTP uses the same approach as SMTP to communicate across the control connection.it uses the 7 bit ASSCII character set. 7

38 Communication over data connection The purpose of the data connection is different from that of the control connection. We want to transfer files through the data connection. A file is to be copied from the server to client is known as RETRIEVING AFT/E. It is done under the supervisor the RETR COMMAND. Client to server STORING AFT/E.(STOR COMMAND) 8

39 Communication over data connection (CONTINUE) a list of directory or file name is to be sent from the server to the client.this is done under the supervisor of the list command. Note: FTP treats a list of directory or file name as a file.it is sent over the data connection. FTP can transfer a file across the data connection by using one of the following three transmission mode : Stream mode,block mode, compressed mode. 9

40 ANONYMOUS FTP To use FTP user needs an account(user name)and password on the remote server. Some times have a set of files available for public access to enable ANONYMOUS FTP. To access these files, a user does not need to have an account or password. Instead the user can use(anonymous) as the user name. and (GUEST) as the password. 10

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