PuTTY (Download of the Month)

PuTTY

At the risk of provoking howls of protest from the Linux purists, this month's download is - gasp! - a Windows program. Simon Tatham's terminal emulator program is a terrific tool for managing Linux servers in a world full of Windows desktops. Not only does it provide serial terminal emulation - useful for configuring routers and testing modems - as well as the deprecated telnet protocol, it also implements the SSH protocol which provides encrypted and strongly authenticated connections to Linux hosts.

To set up PuTTY to connect to a Linux box, just start the program, fill in the host name and select the SSH protocol radio button. Click on the "Connection" page, and fill in your user name, then go back to the "Session" page and remember to save this session's configuration. Now click on the "Open" button, and you'll be prompted for your password, then logged in.

However, for stronger authentication, you should use the puttygen.exe program to generate an SSH2 RSA private/public key pair. Then upload the public key (id_rsa.pub) to your .ssh directory on the server, copy it into the authorized_keys file and make sure it is read/write for you only (chmod 600 authorized_keys). Now, back on the PuTTY Configuration dialog, click on Connection -> SSH -> Auth and use the browse button to point to the Private key file. Save the session configuration again. From now on, you should be able to log in using your private key for authentication.

PuTTY is actually a small collection of programs. Most users are familiar with the main PuTTY program, but overlook the other little gems, missing a lot of functionality. Take the Pageant authentication agent, for example; I always put a shortcut to this little program in my Startup folder so that it appears in the systray. After logging in, I right-click on the Pageant icon (terminal with a hat on top) and choose "Add Key". After selecting my private key and entering the passphrase, I can log in to any session without being prompted for the passphrase - Pageant supplies the required prvate key automatically.

Another quick tip: You can create shortcuts for any session, for fast access: Just make the target for the shortcut be "C:\Program Files\putty\putty.exe" @session-name. Now you can get fast access to your Linux systems.

Finally, for file transfers, check out Martin Prikryl's excellent WinSCP program, which provides a Norton Commander-like interface for encrypted and authenticated file uploads and downloads.

Download from: http://www.chiark.greenend.org.uk/~sgtatham/putty/ (PuTTY), http://winscp.sourceforge.net/eng/ (WinSCP)

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