Centos 6.3. Brand new installation. Did ssh-keygen and files are in my ~/.ssh directory. when I ssh firstname.lastname@example.org, it returns: Permission denied (publickey,gssapi-keyex,gssapi-with-mic). I can't find any tutorials laying out why this is. Can you shed some light on the subject?
Where are you sshing from and where are you sshing to? ssh-keygen needs to be run from the client machine. The private key always stays on that machine, and the public key gets deployed to the system you're connecting to.