Ubuntu 9.10 RSA authentication: ssh fails, filezilla runs fine

Question

This is quite a mistery for me. I usually use passwordless RSA authentication to login into my remote *nix servers with ssh and sftp. Never had any problem until now.

I cannot connect to an Ubuntu 9.10 machine:

user@myclient$ ssh -i .ssh/Ganymede_key [email protected] [...] debug1: Host 'ganymede.server.com' is known and matches the RSA host key. debug1: Found key in /home/user/.ssh/known_hosts:14 debug2: bits set: 494/1024 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: SSH2_MSG_SERVICE_REQUEST sent debug2: service_accept: ssh-userauth debug1: SSH2_MSG_SERVICE_ACCEPT received debug2: key: .ssh/Ganymede_key (0xb96a0ef8) debug2: key: .ssh/Ganymede_key ((nil)) debug1: Authentications that can continue: publickey,password,keyboard-interactive debug1: Next authentication method: publickey debug1: Offering public key: .ssh/Ganymede_key debug2: we sent a publickey packet, wait for reply debug1: Authentications that can continue: publickey,password,keyboard-interactive debug1: Trying private key: .ssh/Ganymede_key debug1: read PEM private key done: type RSA debug2: we sent a publickey packet, wait for reply debug1: Authentications that can continue: publickey,password,keyboard-interactive debug2: we did not send a packet, disable method debug1: Next authentication method: keyboard-interactive debug2: userauth_kbdint debug2: we sent a keyboard-interactive packet, wait for reply debug2: input_userauth_info_req debug2: input_userauth_info_req: num_prompts 1 

Then it falls back to password authentication. If I disable password authentication on the remote machine my connection attempt just fails with a "Permission denied (publickey)." state.

Same thing for sftp from command line.

The "funny" thing is that the exact same RSA key works like a charm with a Filezilla sftp session instead:

12:08:00 Trace: Offered public key from "/home/user/.filezilla/keys/Ganymede_key" 12:08:00 Trace: Offer of public key accepted, trying to authenticate using it. 12:08:01 Trace: Access granted 12:08:01 Trace: Opened channel for session 12:08:01 Trace: Started a shell/command 12:08:01 Status: Connected to ganymede.server.com 12:08:02 Trace: CSftpControlSocket::ConnectParseResponse() 12:08:02 Trace: CSftpControlSocket::ResetOperation(0) 12:08:02 Trace: CControlSocket::ResetOperation(0) 12:08:02 Status: Retrieving directory listing... 12:08:02 Trace: CSftpControlSocket::SendNextCommand() 12:08:02 Trace: CSftpControlSocket::ChangeDirSend() 12:08:02 Command: pwd 12:08:02 Response: Current directory is: "/root" 12:08:02 Trace: CSftpControlSocket::ResetOperation(0) 12:08:02 Trace: CControlSocket::ResetOperation(0) 12:08:02 Trace: CSftpControlSocket::ParseSubcommandResult(0) 12:08:02 Trace: CSftpControlSocket::ListSubcommandResult() 12:08:02 Trace: CSftpControlSocket::ResetOperation(0) 12:08:02 Trace: CControlSocket::ResetOperation(0) 12:08:02 Status: Directory listing successful 

Any thoughts?

M

Answer 1

Your first trace looks somewhat strange. As jneves points out ssh assumes that the file contains your public and private keys. The documentation says that the "identity" is the private key.

 -i identity_file Selects a file from which the identity (private key) for RSA or DSA authentication is read. 

If you do indeed have two keys in one file (had no idea it is possible) you should probably separate them. In any case it seems like you are not conforming to the documentation.

Answer 2

delete you known-hosts file in .ssh in you home folder and it might work.