ssh password-less login to localhost - ssh

Question

I am trying to setup password-less login into my localhost for a distributed computing tutorial. (I've set it up successfully for multiple remote hosts.) I went through the normal steps of generating an rsa key and appending the public key to authorized_keys but I am still prompted for a password. I've also enabled RSAAuthentication and PubKeyAuthentication in /etc/ssh_config. Following other suggestions I've seen, I tried:
chmod go-w ~/
chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys
But the problem persists.
Here is the output from ssh -v localhost:
(tutorial)bnels21-2:tutorial bnels21$ ssh -v localhost
OpenSSH_5.9p1, OpenSSL 0.9.8r 8 Feb 2011
debug1: Reading configuration data /etc/ssh_config
debug1: /etc/ssh_config line 20: Applying options for *
debug1: Connecting to localhost [::1] port 22.
debug1: Connection established.
debug1: identity file /Users/bnels21/.ssh/id_rsa type 1
debug1: identity file /Users/bnels21/.ssh/id_rsa-cert type -1
debug1: identity file /Users/bnels21/.ssh/id_dsa type -1
debug1: identity file /Users/bnels21/.ssh/id_dsa-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.9
debug1: match: OpenSSH_5.9 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.9
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 1c:31:0e:56:93:45:dc:f0:77:6c:bd:90:27:3b:c6:43
debug1: Host 'localhost' is known and matches the RSA host key.
debug1: Found key in /Users/bnels21/.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: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,keyboard-interactive
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /Users/bnels21/.ssh/id_rsa
debug1: Authentications that can continue: publickey,keyboard-interactive
debug1: Offering RSA public key: id_rsa3
debug1: Authentications that can continue: publickey,keyboard-interactive
debug1: Trying private key: /Users/bnels21/.ssh/id_dsa
debug1: Next authentication method: keyboard-interactive
Password:
Any suggestions? I'm running OSX 10.8.

Answer 1

Since you seem to have multiple keys I would assign the specific key to a specific connection in ~/.ssh/config.
Example:
Host local
HostName 127.0.0.1
Port 22
User your_username
IdentityFile ~/.ssh/your_key-id_rsa
Then just try to ssh local.

Answer 2

I had same problem. I checked the system passwd and group files, and discovered that my user and group was not present. To build this files (my user was a domain user) I need to run two commands at cygwin shell:
mkpasswd -l -d > /etc/passwd
mkgroup -l -d > /etc/group
After that, ssh works fine!
Elvys Borges

Answer 3

It looks like you are using protocol version 2.0 when connecting to localhost, so try moving authorized_keys to authorized_keys2.
Source: this post explains the difference between the two keys files.

Answer 4

I was at my wits end... I was under the mistaken impression ssh-copy-id was a Linux-only utility. Finally I just swallowed my pride and typed the command is the macOS Terminal and it worked!
ssh-copy-id me#sshd-server
I don't know what magic ssh-copy-id does, but it just worked. I was able to log in without a password successfully with the simple command:
ssh me#sshd-server
I had zero luck with cat id_rsa.pub >> ~/.ssh/authorized_hosts. Every time I tried ssh'ing to the server it just kept asking me for the passphrase. This is with the correct 600 permission on authorized_hosts and 700 on ~/.ssh.