AWS: Difficulty changing server keys - permission denied (public key)

Question

Struggling with a common problem. The awkward thing is I have followed the guide linked below with success before and I have fully established a working Amazon Web Services LAMP stack running Ubuntu and referencing an RDS database instance.

Here is my problem in this particular scenario, referencing this guide:

http://jeffreifman.com/detailed-wordpress-guide-for-aws/secure-your-instance/

• Launched m1. Micro Instance running Ubuntu 12.04 LTS 64bit.
• Created AWS security keys, downloaded private key to ~/.ssh folder
• SSH in using private key and root login
• Created new admin user
• Added admin user to admin group
• Added user to sudoers list
• Changed user to new user
• Generated new security keypair
• Added new security keypair to authorized_keys list
• Set permissions for .ssh folder to 600
• Edited sshd_config to allow users from ubuntu and new user
• restarted SSH service
• SFTP downloaded private key from tmp folder on server
• .ssh remote folder permissions currently set to 700. Private key to 400, Public key to 600.
• local ~/.ssh/ private key permissions set to 600.

At this point, I have tried SSH'ing back into the server under [email protected] referencing the new private key and I am given the 'permission denied (public key)' warning.

Any help with resolving this would be greatly appreciated.

OpenSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011 debug1: Reading configuration data /etc/ssh_config debug1: /etc/ssh_config line 20: Applying options for * debug1: Connecting to my.ip.address [my.ip.address] port 22. debug1: Connection established. debug1: identity file /Users/myfiles/.ssh/my_key type -1 debug1: identity file /Users/myfiles/.ssh/my_key-cert type -1 debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_6.2 debug1: Remote protocol version 2.0, remote software version OpenSSH_5.9p1 Debian- 5ubuntu1.1 debug1: match: OpenSSH_5.9p1 Debian-5ubuntu1.1 pat OpenSSH_5* 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<1024<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 my.pub.key debug1: Host '54.72.105.9' is known and matches the RSA host key. debug1: Found key in /Users/lloyd/.ssh/known_hosts:6 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_REQUEST sent debug1: SSH2_MSG_SERVICE_ACCEPT received debug1: Authentications that can continue: publickey debug1: Next authentication method: publickey debug1: Offering DSA public key: /Users/lloyd/.ssh/id_fkadmin debug1: Authentications that can continue: publickey debug1: Offering DSA public key: /Users/lloyd/.ssh/id_nutriciaadmin debug1: Authentications that can continue: publickey debug1: Trying private key: /Users/lloyd/.ssh/id_nutriciaadmin debug1: key_parse_private_pem: PEM_read_PrivateKey failed debug1: read PEM private key done: type <unknown> 

Answer 1

You need to tell your local machine which key to use now. You can add it at a root level, but if you have both keys added, it will simply try both of them. The preferred method is to create a conf file for ssh

1. touch ~/.ssh/config then add in

   Host [remote-ip-address] IdentityFile [path to pem file (must be chmod 600)] User [login user] 

2. If that still fails, try debugging the actual ssh connect to see what it's trying to use.

   ssh -v [user@host]