Do not ever change the file permissions of rsa and dsa keys. I was working on troubleshooting some ssh issue and I decided to give read permissions to everyone on file /etc/ssh/ssh_host_rsa_key and the next thing I know I cant login to the server via ssh.
#ssh testbox01 no hostkey alg #ls -l /etc/ssh/ssh_host_rsa_key -rw——-. 1 root ssh_keys 1679 Nov 25 2014 ssh_host_rsa_key #ls -l /etc/ssh/ssh_host_dsa_key -rw——- 1 root root 668 Aug 20 2007 /etc/ssh/ssh_host_dsa_key #ls -l /etc/ssh/ssh_host_rsa_key.pub
-rw-r–r–. 1 root root 382 Nov 25 2014 ssh_host_rsa_key.pub
#ls -l /etc/ssh/ssh_host_dsa_key.pub -rw-r–r–. 1 root root 382 Nov 25 2014 ssh_host_dsa_key.pub
Make sure the permissions are set to 0600 for the private ssh keys and 0644 for public ssh keys(default public keys under /etc/ssh ends with an extension .pub)
