Ssh – How to setup password-less ssh with RSA keys

I am trying to setup a password-less SSH configuration between two machines and I am having a problem. There are a ton of howtos out there that I have followed and have had no success. Here are the steps that I've taken

1. Generate the authentication keys on the client. (Pressed enter when prompted for a passphrase)
   [root@box1:.ssh/$] ssh-keygen -t rsa

2. Copy the public key to the server.
   [root@box1:.ssh/$] scp id_rsa.pub root@box2:.ssh/authorized_keys

3. Verified the authorized key was created successfully on the server

4. Executed the following command:
   [root@box1:.ssh/$] ssh root@box2 ls

And I was still prompted for a password. I read a note on one howto that said "depending on the version of SSH that is running…" (although it did not specify which versions needed this), it might require:

• The public key in .ssh/authorized_keys2
• Permissions of .ssh to 700
• Permissions of .ssh/authorized_keys2 to 640

I also followed those steps and had no success. I have verified that the home, root, and .ssh directories are not writable by group (according to https://unix.stackexchange.com/tags/ssh/info).

Anyone have any ideas what I'm missing?

Thanks

EDIT: I also copied the public key to the second box using the ssh-copy-id command and that generated the .ssh/authorized_keys file.

[root@box1:.ssh/$] ssh-copy-id -i id_rsa.pub root@box2

EDIT2: Including version information

// box1 (system keys were generated on)

• Linux 2.6.34
• OpenSSH_5.5p1 Debian-6, OpenSSL 0.9.8o 01 June 2010

// box2

• Linux 2.6.33
• Dropbear client v0.52

EDIT3: Debug output

[root@box1:.ssh/$] ssh -vvv root@box2 ls
OpenSSH_5.5p1 Debian-6, OpenSSL 0.9.8o 01 Jun 2010
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to box2 [box2] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug3: Not a RSA1 key file /root/.ssh/id_rsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /root/.ssh/id_rsa type 1
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
debug1: identity file /root/.ssh/id_rsa-cert type -1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: identity file /root/.ssh/id_dsa-cert type -1
debug1: Remote protocol version 2.0, remote software version dropbear_0.52
debug1: no match: dropbear_0.52
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.5p1 Debian-6
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit:
diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-    
group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit:
ssh-rsa-cert-v00@openssh.com,ssh-dss-cert-v00@openssh.com,ssh-rsa,ssh-dss
debug2: kex_parse_kexinit:
aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-    
cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysatoe
debug2: kex_parse_kexinit:
aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-    
cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysatoe
debug2: kex_parse_kexinit:
hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-    
sha1-96,hmac-md5-96
debug2: kex_parse_kexinit:
hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-
sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit:
aes128-ctr,3des-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes256-cbc,twofish256-cbc,twofish-
cbc,twofish128-cbc,blowfish-cbc
debug2: kex_parse_kexinit:
aes128-ctr,3des-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes256-cbc,twofish256-cbc,twofish-
cbc,twofish128-cbc,blowfish-cbc
debug2: kex_parse_kexinit: hmac-sha1-96,hmac-sha1,hmac-md5
debug2: kex_parse_kexinit: hmac-sha1-96,hmac-sha1,hmac-md5
debug2: kex_parse_kexinit: zlib,zlib@openssh.com,none
debug2: kex_parse_kexinit: zlib,zlib@openssh.com,none
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_setup: found hmac-md5
debug1: kex: server->client aes128-ctr hmac-md5 none
debug2: mac_setup: found hmac-md5
debug1: kex: client->server aes128-ctr hmac-md5 none
debug2: dh_gen_key: priv key bits set: 132/256
debug2: bits set: 515/1024
debug1: sending SSH2_MSG_KEXDH_INIT
debug1: expecting SSH2_MSG_KEXDH_REPLY
debug3: check_host_in_hostfile: host 192.168.20.10 filename
/root/.ssh/known_hosts
debug3: check_host_in_hostfile: host 192.168.20.10 filename
/root/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 3
debug1: Host 'box2' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:3
debug2: bits set: 522/1024
debug1: ssh_rsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /root/.ssh/id_rsa (0x54b1c340)
debug2: key: /root/.ssh/id_dsa ((nil))
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred
gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /root/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /root/.ssh/id_dsa
debug3: no such identity: /root/.ssh/id_dsa
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password

EDIT4: Another interesting development. Instead of generating the keys on box1 (running OpenSSH) and copying them to box2 (running dropbear) I did it in reverse:

[root@box2:.ssh/$] dropbearkey -t rsa -f id_rsa
[root@box2:.ssh/$] dropbearkey -y -f id_rsa | grep "^ssh-rsa" >> authorized_keys
[root@box2:.ssh/$] scp authorized_keys root@box1:.ssh/

And with that I am successfully able to issue commands password-less from box2 to box1 ONLY if I specify the ID file:
[root@box2:.ssh/$] ssh -i id_rsa root@box1 ls

Still unable to issue commands from box1 (OpenSSH) to box2 (dropbear).