[Planetlab-users] useful ssh tools/links

[Aaron K. <al...@CS...>]

Hi all, I thought I'd put together an email of some useful ssh tools and 
websites, if you are new to ssh, or not aware of some ways to make using it 
easier.

First, this document has a good overview of the most common uses of ssh:
http://kimmo.suominen.com/ssh/

Also, if you haven't seen this document, it outlines some basic points on 
using ssh keys on PlanetLab:
https://www.planet-lab.org/db/web_accounts/ssh_public_key.php

Most linux systems will have ssh (OpenSSH) already installed for you, but if 
this is not the case, visit http://openssh.com/ for official releases for 
numerous linux-based platforms.

If you are using Windows based machines, several options exist. There are 
commercial ssh clients like SecureCRT:
http://www.vandyke.com/products/securecrt/
or freeware clients like putty:
http://www.chiark.greenend.org.uk/~sgtatham/putty/

Another option worth mentioning is cygwin. For windows, its a complete linux 
like environment. For more information, see:
http://cygwin.com/
If you install it, make sure to add OpenSSH to the list of packages to 
install, as I last checked, it was not enabled by default. Once installed, 
this will give you a command prompt running the common bash shell, and you 
can use ssh as if you were on a linux box.

As for Macintoshes, I'll have to let someone else fill in on which tools work 
well. :)

The other reason for this email was to introduce ssh-agent and similar 
programs. Since PlanetLab strongly suggests that you use a passphrase on your 
private ssh key, it can be very cumbersome to have to type in the passphrase 
everytime you login to a node. This is especially true if you have scripts to 
handle logging into many machines. Without this passphrase, if your key is 
compromised, it can be used by anyone to access your slice, which puts you at 
risk. 

ssh-agent is a program available from the OpenSSH distribution that allows you 
to add your private keys to a running agent program on your computer and only 
have to type in the passphrase once, where the keys are then stored in 
memory. Then, all ssh operations (including scp - secure file copy), 
transparently contact the agent and use the key there, so you don't have to 
type in the passphrase more than once.

For information on how to setup ssh-agent:
http://kimmo.suominen.com/ssh/#ssh-agent
http://www.caip.rutgers.edu/~vincentm/LINKS/sshagent.html

For windows, there is a similar program available from the same authors who 
wrote putty, called Pageant. This works in the same way, where you add your 
keys to the Pageant application after its running, and putty contacts Pageant 
for the authorization while logging in. See the putty website above for more 
specific documentation.

Aaron