Lazaro Raisel Milians Alvarez de la Campa wrote:
La idea de usar ftp es buena, pero me gusta más por SCP, pero ahí es
donde tengo el problema, por SCP necesito pasar el password y no sé como.
Hola, te mando, y de paso para la lista, esta guia para hacer eso, es un
poco largo y en ingles, tomado del sitio http://www.thegeekstuff.com
Suerte,
dermidio.
Perform SSH and SCP Without Entering Password on openSSH
In this article, I’ll explain how to perform ssh and scp without
entering the password using the SSH Public Key authentication with SSH
Agent on openSSH
There are two levels of security in the SSH key based authentication. In
order for you to login, you need both the private key and the
passphrase. Even if one of them is compromised, attacker still cannot
login to your account, as both of them are needed to login. This is far
better than typical password based authentication, where if the password
is compromised, attacker can gain access to the system.
There are two ways to perform ssh and scp without entering the password:
1. *No passphrase.* While creating key pair, leave the passphrase
empty. Use this option for the automated batch processing. for
e.g. if you are running a cron job to copy files between machines
this is suitable option.
2. *Use passphrase and SSH Agent. *If you are using ssh and scp
interactively from the command-line and you don’t want to use the
password everytime you perform ssh or scp, I don’t recommend the
previous option (no passphrase), as you’ve eliminated one level of
security in the ssh key based authentication. Instead, use the
passphrase while creating the key pair and use SSH Agent to
perform ssh and scp without having to enter the password everytime
as explained in the steps below.
Following 8 steps explains how to perform SSH and SCP from local-host to
a remote-host without entering the password on openSSH system
1. Verify that local-host and remote-host is running openSSH
[local-host]$*ssh -V*
OpenSSH_4.3p2, OpenSSL 0.9.8b 04 May 2006
[remote-host]$*ssh -V*
OpenSSH_4.3p2, OpenSSL 0.9.8b 04 May 2006
2. Generate key-pair on the local-host using ssh-keygen
[local-host]$*ssh-keygen*
Generating public/private rsa key pair.
Enter file in which to save the key (/home/jsmith/.ssh/id_rsa):*<Hit enter>*
Enter passphrase (empty for no passphrase):*<Enter your passphrase here>*
Enter same passphrase again:*<Enter your passphrase again>*
Your identification has been saved in /home/jsmith/.ssh/id_rsa.
Your public key has been saved in /home/jsmith/.ssh/id_rsa.pub.
The key fingerprint is:
31:3a:5d:dc:bc:81:81:71:be:31:2b:11:b8:e8:39:a0 jsmith@local-host
The public key and private key are typically stored in .ssh folder under
your home directory. In this example, it is under /home/jsmith/.sshd.
You should not share the private key with anybody.
By default the ssh-keygen on openSSH generates RSA key pair. You can
also generate DSA key pair using: *ssh-keygen -t dsa* command.
3. Install public key on the remote-host.
Copy the content of the public key from the local-host and paste it to
the /home/jsmith/.ssh/authorized_keys on the remote-host. If the
/home/jsmith/.ssh/authorized_keys already has some other public key, you
can append this to the end of it. If the .ssh directory under your home
directory on remote-host doesn’t exist, please create it.
[remote-host]$*vi ~/.ssh/authorized_keys*
ssh-rsa ABIwAAAQEAzRPh9rWfjZ1+7Q369zsBEa7wS1RxzWR jsmith@local-host
In simple words, copy the local-host:/home/jsmith/.ssh/id_rsa.pub to
remote-host:/home/jsmith/.ssh/authorized_keys
4. Give appropriate permission to the .ssh directory on the
remote-host.
[remote-host]$*chmod 755 ~/.ssh*
[remote-host]$*chmod 644 ~/.ssh/authorized_keys*
5. Login from the local-host to remote-host using the SSH key
authentication to verify whether it works properly.
[local-host]$*<You are on local-host here>*
**[local-host]$*ssh -l jsmith remote-host*
Enter passphrase for key '/home/jsmith/.ssh/id_rsa':*<Enter your passphrase
here>*
Last login: Sat Jun 07 2008 23:03:04 -0700 from 192.168.1.102
No mail.
[remote-host]$*<You are on remote-host here>*
6. Start the SSH Agent on local-host to perform ssh and scp
without having to enter the passphrase several times.
Verify whether SSH agent is already running, if not start it as shown
below.* *
[local-host]$ ps -ef | grep ssh-agent
511 9789 9425 0 00:05 pts/1 00:00:00 grep ssh-agent
[local-host]$*ssh-agent $SHELL*
[local-host]$ ps -ef | grep ssh-agent
511 9791 9790 0 00:05 ? 00:00:00 ssh-agent /bin/bash
511 9793 9790 0 00:05 pts/1 00:00:00 grep ssh-agent
7. Load the private key to the SSH agent on the local-host.
[local-host]$*ssh-add*
Enter passphrase for /home/jsmith/.ssh/id_rsa:*<Enter your passphrase here>*
Identity added: /home/jsmith/.ssh/id_rsa (/home/jsmith/.ssh/id_rsa)
Following are the different options available in the ssh-add:
* ssh-add <key-file-name>: Load a specific key file.
* ssh-add -l: List all the key loaded in the ssh agent.
* ssh-add -d <key-file-name>: Delete a specificy key from the ssh agent
* ssh-add -D: Delete all key
8. Perform SSH or SCP to remote-home from local-host without
entering the password.
[local-host]$*<You are on local-host here>*
[local-host]$*ssh -l jsmith remote-host*
Last login: Sat Jun 07 2008 23:03:04 -0700 from 192.168.1.102
No mail.
*<ssh did not ask for passphrase this time>*
[remote-host]$*<You are on remote-host here>
*****
Fin.
*
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