How to setup SSH password-less login on Red Hat Enterprise Linux 4 and below

Solution Verified - Updated

Environment

  • Red Hat Enterprise Linux 3
  • Red Hat Enterprise Linux 4
  • openssh

Issue

  • How to setup SSH password-less login on Red Hat Enterprise Linux 4 and below

Resolution

To enable key-based authentication perform the following steps:

1. On the ssh client, generate a new ssh key using the ssh-keygen command. It will ask for a path to save the file, and a passphrase, just press "enter" to select all default values ( specifically for a blank pasphrase) and to return to console.

[user@ssh-client ~]$ ssh-keygen -t dsa

2. Copy your id_dsa.pub file to the server running sshd service using scp or a suitable method. Following example uses scp command:

[user@ssh-client ~]$ scp ~/.ssh/id_dsa.pub user@ssh-server:~/id_dsa.pub

3. On the ssh server side, to allow ssh client to connect to the server running sshd service, add the content of the id_dsa.pub file from another system using the following format:

[user@ssh-server ~]$ cat id_dsa.pub >> ~/.ssh/authorized_keys

4. After setting up the authorized_keys file, run the following command to setup the permission correctly on the sshd server.

[user@ssh-server ~]$ chmod 0700 ~/.ssh -R

Now whenever the ssh command is used between those two system, it will not ask for the password.

Comment

  • For security reasons, it is preferred that a passphrase be used for creating ssh authentication key.
  • For Red Hat Enterprise Linux 5 and above, refer to How do I setup SSH passwordless login?
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