Passwordless SSH

To set up password-less ssh/scp between two accounts on two different machines :

1. Install SSH on each machine, and in each of the two accounts, run ssh-keygen with an empty passphrase :

bob@pluto:/export/home/bob> ssh-keygen Generating public/private rsa1 key pair. Enter file in which to save the key (/export/home/bob/.ssh/identity): Created directory '/export/home/bob/.ssh'. Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /export/home/bob/.ssh/identity. Your public key has been saved in /export/home/bob/.ssh/identity.pub. The key fingerprint is: 48:bc:98:6a:9b:dc:8d:ee:a5:66:02:45:ce:6e:db bob@pluto bob@pluto:/export/home/bob>

2. then on each machine, add the contents of $HOME/.ssh/identity.pub from the OTHER machine to $HOME/.ssh/authorized_keys on the local machine (authorized_keys is a bit like a .rhosts file) ( identity.pub should look something like
1024 35 160113598328315770347757629917900809305107052156577 35309230295215401023914018627645367660366634152222008662730523500914536747457721973246144358939975391572463683312532362580794046759060783340 4305418708539664884348021852629799444102754790417057317676624046572566499195728210728140 74215982344694643792671 bob@europa

(all that is on one line!)

Then you should be able to run 'ssh other_host' or 'scp myfile other_host:myfile.bak' from each and not get a password prompt.

N.B. The first time you connect to a new remote machine you will get a warning :

Warning: Permanently added the RSA1 host key for IP address 'a.b.c.d' to the list of known hosts.
and it adds the remote machine's key to $HOME/.ssh/known_hosts

You should only set this up for situations where automated remote copying needs to be done, not just to avoid typing passwords..
If you have any problems you can use 'ssh -v other_host' and you will see verbose messages as it proceeds, which usually pinpoints where the problem lies.