PuTTY is a client program for the SSH, Telnet and Rlogin network protocols.
These protocols are all used to run a remote session on a computer, over a network. PuTTY implements the client end of that session: the end at which the session is displayed, rather than the end at which it runs.
In really simple terms: you run PuTTY on a Windows machine, and tell it to connect to (for example) a Unix machine. PuTTY opens a window. Then, anything you type into that window is sent straight to the Unix machine, and everything the Unix machine sends back is displayed in the window. So you can work on the Unix machine as if you were sitting at its console, while actually sitting somewhere else.
This download includes the following tools:
- PuTTY (the Telnet and SSH client itself)
- PSCP (an SCP client, i.e. command-line secure file copy)
- PSFTP (an SFTP client, i.e. general file transfer sessions much like FTP)
- PuTTYtel (a Telnet-only client)
- Plink (a command-line interface to the PuTTY back ends)
- Pageant (an SSH authentication agent for PuTTY, PSCP and Plink)
- PuTTYgen (an RSA and DSA key generation utility).
- Security fix: PuTTY no longer retains the private half of users' keys in memory by mistake after authenticating with them. See private-key-not-wiped-2. (Sorry! We thought we'd fixed that in 0.63, but missed one.)
- Support for SSH connection sharing, so that multiple instances of PuTTY to the same host can share a single SSH connection instead of all having to log in independently.
- Command-line and configuration option to specify the expected host key(s).
- Defaults change: PuTTY now defaults to SSH-2 only, instead of its previous default of SSH-2 preferred.
- Local socket errors in port-forwarded connections are now recorded in the PuTTY Event Log.
- Bug fix: repeat key exchanges in the middle of an SSH session now never cause an annoying interactive host key prompt.
- Bug fix: reset the bolded-text default setting back to what it used to be. (0.63 set it to something wrong, as a side effect of refactoring.)
- Bug fix: IPv6 literals are handled sensibly throughout the suite, if you enclose them in square brackets to prevent the colons being mistaken for a :port suffix.
- Bug fix: IPv6 dynamic port forwardings should work again.