Difference between revisions of "Passwordless logins"

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A passwordless login is possible via [[ssh]] if you have established a trust relationship between two computers like this:
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A passwordless login is possible via [[ssh]] if you have established a trust relationship between two computers.
  scorpio:~ # ssh-keygen -t dsa
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;Goal: You want to log in using ssh to a computer. You do not want to enter a password, however it needs to be secured.
 +
 
 +
;Solution: Establish a trust relationship so your desktop's ssh key is authorized on your server like this:
 +
  desktop:~ # ssh-keygen -t dsa
 
  Generating public/private dsa key pair.
 
  Generating public/private dsa key pair.
 
  Enter file in which to save the key (/root/.ssh/id_dsa):
 
  Enter file in which to save the key (/root/.ssh/id_dsa):
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  The key fingerprint is:
 
  The key fingerprint is:
 
  1c:9a:b8:03:ab:04:b3:7b:75:49:99:8c:51:79:5d:06 root@scorpio
 
  1c:9a:b8:03:ab:04:b3:7b:75:49:99:8c:51:79:5d:06 root@scorpio
  scorpio:~ # scp .ssh/id_dsa.pub root@foo:~/.ssh/authorized_keys
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  desktop:~ # scp .ssh/id_dsa.pub root@server:~/.ssh/authorized_keys
In this example, you create a key pair with no passphrase and distribute the public key from the computer ''scorpio'' to ''foo''. The user root from scorpio no longer needs to authenticate with his password, he can log in to foo from scorpio with the [[command]]
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In this example, you create a key pair with no passphrase and distribute the public key from the computer ''desktop'' to ''server''. The user root from ''desktop'' no longer needs to authenticate with his password, he can log in to ''server'' from ''desktop'' with the [[command]]
  scorpio:~ # ssh foo
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  desktop:~ # ssh server
  Welcome to foo.
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  Welcome to server.
  foo:~ #
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  server:~ #

Revision as of 07:27, 6 April 2009

A passwordless login is possible via ssh if you have established a trust relationship between two computers.

Goal
You want to log in using ssh to a computer. You do not want to enter a password, however it needs to be secured.
Solution
Establish a trust relationship so your desktop's ssh key is authorized on your server like this:
desktop:~ # ssh-keygen -t dsa
Generating public/private dsa key pair.
Enter file in which to save the key (/root/.ssh/id_dsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_dsa.
Your public key has been saved in /root/.ssh/id_dsa.pub.
The key fingerprint is:
1c:9a:b8:03:ab:04:b3:7b:75:49:99:8c:51:79:5d:06 root@scorpio
desktop:~ # scp .ssh/id_dsa.pub root@server:~/.ssh/authorized_keys

In this example, you create a key pair with no passphrase and distribute the public key from the computer desktop to server. The user root from desktop no longer needs to authenticate with his password, he can log in to server from desktop with the command

desktop:~ # ssh server
Welcome to server.
server:~ #