I am running a CentOS 6.5 machine remotely via SSH. I use RSA keys and have disabled password authentication. The problem that I am having is that whenever I add a new user and want him/her to log in via SSH, they are denied access.

At first this seemed like a simple problem. Theses are what I have already tried:

  • Checked the pub key for obvious errors
  • Ensured the right permissions on authorized_keys and ~/.ssh
  • Made sure they're in the AllowUsers list in ssh_config
  • Checked firewall permissions
  • Made sure their private key is being used
  • Restarted SSHD

Here is what I have set in sshd_config:

PermitRootLogin no
AllowUsers keving moman muser

And this is what my log is telling me:

Login attempted when not in AllowUsers list:
    muser : 3 Time(s)
    root : 127 Time(s)

Why is SSH not allowing login while the AllowUsers list obviously lists muser? Is there another place where this could be set?

UPDATE: I attempted a login to that account on my machine after adding my pub key to the user's authorized_keys file with the verbose flag -v. These are the results (with a fake IP and server host key for security reasons):

$ ssh -v mattm@
OpenSSH_6.6.1, OpenSSL 1.0.1i 6 Aug 2014
debug1: Reading configuration data /c/Users/[user]/.ssh/config
debug1: Connecting to [] port 22.
debug1: Connection established.
debug1: identity file /c/Users/[user]/.ssh/id_rsa type 1
debug1: identity file /c/Users/[user]/.ssh/id_rsa-cert type -1
debug1: identity file /c/Users/[user]/.ssh/id_dsa type -1
debug1: identity file /c/Users/[user]/.ssh/id_dsa-cert type -1
debug1: identity file /c/Users/[user]/.ssh/id_ecdsa type -1
debug1: identity file /c/Users/[user]/.ssh/id_ecdsa-cert type -1
debug1: identity file /c/Users/[user]/.ssh/id_ed25519 type -1
debug1: identity file /c/Users/[user]/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.6.1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3
debug1: match: OpenSSH_5.3 pat OpenSSH_5* compat 0x0c000000
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<3072<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Server host key: RSA [censored]
debug1: Host '' is known and matches the RSA host key.
debug1: Found key in /c/Users/[user]/.ssh/known_hosts:4
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /c/Users/[user]/.ssh/id_rsa
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic
debug1: Trying private key: /c/Users/[user]/.ssh/id_dsa
debug1: Trying private key: /c/Users/[user]/.ssh/id_ecdsa
debug1: Trying private key: /c/Users/[user]/.ssh/id_ed25519
debug1: No more authentication methods to try.
Permission denied (publickey,gssapi-keyex,gssapi-with-mic).
  • 2
    Did you restart sshd? – Michael Hampton Oct 21 '14 at 1:05
  • If you have a Linux client, what happens if you turn on verbose logging (-v). Similarly, are you in a position to run sshd in the foreground with logging ? Lastly, did you restart SSH after modifying AllowUsers ? – davidgo Oct 21 '14 at 1:06
  • @davidgo I updated the question with the putput you mentioned. – gillytech Oct 21 '14 at 2:10
  • @MichaelHampton Sure did. – gillytech Oct 21 '14 at 2:11
  • Can you post the output from /var/log/secure through a login attempt? – toppledwagon Oct 21 '14 at 4:13

As @toppledwagon suggests in the comments to my question, I checked /var/log/security and sure enough there was an entry for bad permissions on the ~/.ssh/authorized_keys tree including the home directory.

After making these edits I was able to log in to the user's account via ssh with RSA keys:

$ chmod g-w /home/your_user
$ chmod 700 /home/your_user/.ssh
$ chmod 600 /home/your_user/.ssh/authorized_keys

Ref: http://www.daveperrett.com/articles/2010/09/14/ssh-authentication-refused/

After adjusting these permissions I was able to log in. It was interesting to note that I had the .ssh dir and authorized_keys file already set to 700 and 600 respectively. For some reason the home directory was not set properly.

Thanks to all who helped in the comments.

  1. In /etc/ssh/sshd_config add the group of your user to AllowGroups.
  2. Restart sshd service sshd restart

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.