Can't ssh from Ubuntu to RHEL or CentOS

Question

I am trying to setup publickey based authenitcation for 2 different boxes. One RHEL another on e is CentOS. I am having same issue with both where ssh fails and falls back to password based authentication. Error that seems to be causing this is quite obscure:

debug1: Unspecified GSS failure.  Minor code may provide more information

Credentials cache file '/tmp/krb5cc_1000' not found

Both boxes are completely unrelated. I have my public key in .ssh/authorized_keys file on both boxes, all permissions are checked and good(700 for .ssh and 600 for internals) I have bunch of other servers that are running on various flavors(Gentoo, Fedora, FreeBSD etc.) and publickey ssh works just fine, but CentOS and RHEL giving me this for some reason :(

Anyone experienced this before? I am not even sure how to further analyze this issue :(

Answer 1

The error that you're getting is related to Kerberos Authentication.

I'm going to assume you're NOT using Kerberos and you have your keys setup properly.

Try adding/changing these in your ssh config files

sshd_config

GSSAPIAuthentication no

GSSAPICleanupCredentials no

KerberosAuthentication no

KerberosOrLocalPasswd no

KerberosTicketCleanup no

ssh_config

RSAAuthentication yes

PasswordAuthentication yes

HostbasedAuthentication no

GSSAPIAuthentication no

GSSAPIDelegateCredentials no

Answer 2

Just wanted to add a comment in case anyone else comes across this error - I was having the same issue, it turns out it was SELinux permissions mucking with the SSH authorized_keys access.

You can use restorecon -r /root/.ssh to restore permissions, or turn off SELinux completely.