ssh publickey set up

Ubuntu to Centos

Generating RSA Keys

mkdir ~/.ssh
chmod 700 ~/.ssh
ssh-keygen -t rsa

Transfer Client Key to Host

ssh-copy-id <username>@<host>

or

cp authorized_keys authorized_keys_Backup
cat id_rsa.pub >> authorized_keys

troubleshooting

configure /etc/ssh/sshd_config

On the host computer, ensure that the /etc/ssh/sshd_config contains the following lines, and that they are uncommented;

PubkeyAuthentication yes
RSAAuthentication yes

Centos specific

SELinux permissions prevented the SSH service from accessing the authorized_keys.

Use

restorecon -r /root/.ssh

to restore permissions, or turn off SELinux completely.

source:

https://help.ubuntu.com/community/SSH/OpenSSH/Keys

http://serverfault.com/questions/147859/cant-ssh-from-ubuntu-to-rhel-or-centos

random thought

It cost me several hours to get it works.

  1. I do not know the ssh programe do not give me any debug information or it is my fault failing to find them?
  2. I really need to have an general idea (read the document) and then try. To try and error directly is really not good.