SSH Key Exchange (SSH no password)

Paul — Thu, 30 Oct 2008 15:12:07 +0000

I’m not sure if it was just me being a bit dense or the fact that tutorials on the subject where really confusing, but I’d always struggled to get this working. So, I thought that now I’ve cracked it I’ll do my own little tutorial for others out there that may still be a little bit stuck.

The first thing you have to do is generate the keys, this is done on the machine that will be connecting from:
ssh-keygen -t rsa
This will generate the private and public keys need, they will be put in “~/.ssh/” by default called “id_rsa.pub”(the public key) and “id_rsa” the private key.
Now you need to copy this public key, “id_rsa.pub”, to the machine you will be connecting to, choose what ever method your comfortable with, ssh, ftp, smb – what ever
Now all you need to do is add this key to the file “~/.ssh/authorized_keys2″, the easist way is:
cat id_rsa.pub >> ~/.ssh/authorized_keys2
Then your done, you should no longer be prompted for a password when connecting.

Note: if this is the first time you are connecting it will still prompt you to add the machine to known hosts.

SSH Automatic Password Entry

Paul — Tue, 09 Sep 2008 12:50:48 +0000

I always thought that to use ssh in a shell script you had to authenticate with keys(no always possible) but I’ve just discovered a really useful way of passing the password directly to the ssh client though a shell script. This could have saved me so much faffing about in the past if only I’d found it sooner. Anyways here it is:

#!/bin/sh

PASSWORD=”{password}”

expect -c “set timeout -1;\
spawn ssh {servername} -l {username} \”{command}\”;\
match_max 100000;\
expect *password:*;\
send — $PASSWORD\r;\
interact;” | tail -n+3

PS this is really not all that secure so I’d only use as a last resort (so be warned).

Paul Brunt » ssh linux shell

SSH Key Exchange (SSH no password)

SSH Automatic Password Entry