Secure Shell or SSH is a network protocol that allows data to be exchanged using a secure channel between two networked devices.
Used primarily on Linux and Unix based systems to access shell accounts .
SSH uses public-key cryptography to authenticate the remote computer and allow the remote computer to authenticate the user, if necessary
SSH is a protocol that can be used for many applications. Some of the applications below may require features that are only available or compatible with specific SSH clients or servers. For example, using the SSH protocol to implement a VPN is possible, but presently only with the OpenSSH server and client implementation.
for login to a shell on a remote host (replacing Telnet and rlogin)
for executing a single command on a remote host (replacing rsh)
for copying files from a local server to a remote host. See SCP , as an alternative for rcp
in combination with SFTP , as a secure alternative to FTP file transfer
in combination with rsync to backup, copy and mirror files efficiently and securely
for port forwarding or tunneling a port (not to be confused with a VPN which routes packets between different networks or bridges two broadcast domains into one.).
for using as a full-fledged encrypted VPN . Note that only OpenSSH server and client supports this feature.
for forwarding X11 through multiple hosts
for browsing the web through an encrypted proxy connection with SSH clients that support the SOCKS protocol .
for securely mounting a directory on a remote server as filesystem on a local computer using SSHFS .
for automated remote monitoring and management of servers through one or more of the mechanisms as discussed above.
PuTTY is a terminal emulator application
which can act as a client for the ssh, telnet,
rlogin and raw TCP computing protocols.
Features of PuTTY
Storing of hosts and preferences for later use.
Control over the ssh encryption key and protocol version.
Control over the port forwarding with ssh(local, remote or dynamic port forwarding)
Its supports IPv6
Support for local serial port connections
Self contained executable requires no installation
Virtual network computing is a graphical
desktop sharing system that uses the RFB
protocol to remotely control another
Connecting the Windows OS
What software can be used?
Security and encryption
Telnet is an abbreviation for Terminal
It is a general purpose client server application program which is used as a standard TCP/IP protocol for VTD as proposed by ISO.
It establishes the connection to a remote system in such a way that the local terminal appears to be a terminal at the remote system.
How does Local Login occur?
When a user logs in into a time-sharing system it is called local login.
As the user types at terminal the keystrokes are accepted by the terminal driver which are in turn sent to OS.
The OS interprets the characters and invokes the desired application program accordingly.
How Does Remote-login Occur in Telnet?
Here the Telnet client and server programs come into use.
The keystrokes are sent to terminal driver where local OS accepts it but does not interpret it.
The characters are sent to telnet client and transformed into NVT characters and delivers them to local TCP/IP protocol stack.
The command or text in NVT form travels through the internet to TCP/IP stack of remote machine.
Here characters are then delivered to OS and passed to Telnet server which changes character into understandable form.