ssh connection using RSA key keep asking password

Question

I'm trying to set-up SSH connections without password to many servers, using RSA key. It works well for most of them but one is giving me some trouble.

The most common issue I've found in the past is permissions problems on .ssh or authorized_keys on the remote host, but here they seem correct, like this:

drwx------  ~/.ssh
-rw-r--r--  ~/.ssh/authorized_keys

Here is output of ssh -v command to this server (I just changed hostname and IP):

Sun_SSH_1.1.3, SSH protocols 1.5/2.0, OpenSSL 0x0090704f
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Rhosts Authentication disabled, originating port will not be trusted.
debug1: ssh_connect: needpriv 0
debug1: Connecting to myhost.mydomain.com [123.123.123.123] port 22.
debug1: Connection established.
debug1: identity file /export/home/webdev1/.ssh/identity type -1
debug1: identity file /export/home/webdev1/.ssh/id_rsa type 1
debug1: identity file /export/home/webdev1/.ssh/id_dsa type -1
debug1: Remote protocol version 1.5, remote software version 1.2.31
debug1: match: 1.2.31 pat 1.2.1*,1.2.2*,1.2.3*
debug1: Local version string SSH-1.5-Sun_SSH_1.1.3
debug1: Waiting for server public key.
debug1: Received server public key (768 bits) and host key (1024 bits).
debug1: Host 'myhost.mydomain.com' is known and matches the RSA1 host key.
debug1: Found key in /export/home/webdev1/.ssh/known_hosts:6
debug1: Encryption type: 3des
debug1: Sent encrypted session key.
debug1: cipher_init: set keylen (16 -> 32)
debug1: cipher_init: set keylen (16 -> 32)
debug1: Installing crc compensation attack detector.
debug1: Received encrypted confirmation.
debug1: Doing password authentication.

I suspect it could be due to the SSH version. Another server which works gives me the following output (remote protocol version 2.0 instead of 1.5):

debug1: Remote protocol version 2.0, remote software version Sun_SSH_1.1.3
debug1: match: Sun_SSH_1.1.3 pat Sun_SSH_1.1.*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-Sun_SSH_1.1.3

Any clue? Thanks for your help.

Answer 1

try just

chmod -R 600 ~/.ssh/

Maybe the group/global read permission is causing an issue.

Answer 2

The server may be configured to refuse public-key-based, password-less authentication. I do not know about Sun_SSH, but in OpenSSH (the most prevalent SSH implementation on Linux/*BSD systems) this is a matter of changing some settings in /etc/ssh/ssd_config (options RSAAuthentication for v1 protocol, PubkeyAuthentication for v2).