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lamp_scaler
Asked: 2011-07-18 19:28:41 +0800 CST

ssh with key login failed from Mac OSX to CentOS 5 remote server

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I'm trying to setup passwordless login for from my mac to my remote server running CentOS with public key authentication for "user1".

I used $ ssh-keygen -t rsa to setup a public key on my mac and then copied the mykey.pub file over to the CentOS user1's .ssh dir and then did a 

cat mykey.pub >> authorized_keys

in the .ssh dir.

I've also set the permissions for the .ssh dir to 700 and the authorized_keys to 600.

when I do a:

ssh [email protected]

It still prompts me for my password. What's going on?

Here is a copy of my sshd_config file on the remote machine:

Protocol 2

SyslogFacility AUTHPRIV

PermitRootLogin no

RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile  .ssh/authorized_keys

PasswordAuthentication yes
PermitEmptyPasswords no

ChallengeResponseAuthentication no

GSSAPIAuthentication yes
GSSAPICleanupCredentials yes

UsePAM no

AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES 
AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT 
AcceptEnv LC_IDENTIFICATION LC_ALL

X11Forwarding yes

Subsystem   sftp    /usr/libexec/openssh/sftp-server

More info:

Here is my output for ssh -v. I think the system defaulted to using the id_rsa.pub instead of the mykey.pub and the mykey (private key file) that I named.

OpenSSH_5.2p1, OpenSSL 0.9.8r 8 Feb 2011
debug1: Reading configuration data /etc/ssh_config
debug1: Connecting to myremoteserver.com [1.1.1.1 (fake IP)] port 22.
debug1: Connection established.
debug1: identity file /Users/LocalUser/.ssh/identity type -1
debug1: identity file /Users/LocalUser/.ssh/id_rsa type -1
debug1: identity file /Users/LocalUser/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3
debug1: match: OpenSSH_4.3 pat OpenSSH_4*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.2
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: Host 'myremoteserver.com' is known and matches the RSA host key.
debug1: Found key in /Users/LocalUser/.ssh/known_hosts:11
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug1: Next authentication method: publickey
debug1: Trying private key: /Users/LocalUser/.ssh/identity
debug1: Trying private key: /Users/LocalUser/.ssh/id_rsa
debug1: Trying private key: /Users/LocalUser/.ssh/id_dsa
debug1: Next authentication method: password

How does one tell the system to use mykey instead of the id_rsa?

linux centos ssh public-key private-key

2 Answers

  1. When you create a public key, you are also creating a private key, called id_rsa

    The id_rsa file should be in the connecting users .ssh folder, and the permissions set as you described for the server.

    If it is present, then try 

    ssh -vvv <server>

    This will give you more detailed logging and will provide more clues as to why it isn't working.

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  2. Best Answer

    Looks like your real question is right at the end:

    How does one tell the system to use mykey instead of the id_rsa?

    With the -i flag.

    FTFM:

    -i identity_file
    Selects a file from which the identity (private key) for RSA or
    DSA authentication is read.  The default is ~/.ssh/identity for
    protocol version 1, and ~/.ssh/id_rsa and ~/.ssh/id_dsa for pro-
    tocol version 2.  Identity files may also be specified on a per-
    host basis in the configuration file.  It is possible to have
    multiple -i options (and multiple identities specified in config-
    uration files).

    So then:

    ssh -i mykey [email protected]
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