Arch Linux

Description:
I want to access my server via ssh and dyndns.
I am having a valid private key on the client which works without problems in the local network.
Now I am outside and ssh always wants a passwort although password authentification is disabled on the server.
When I use WinSCP to access I don't have any problems.

ssh XX -i .ssh/server -l XX -v
OpenSSH_5.8p2, OpenSSL 1.0.0d 8 Feb 2011
debug1: Reading configuration data /home/XX/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Connecting to XX port 22.
debug1: Connection established.
debug1: identity file .ssh/server type -1
debug1: identity file .ssh/server-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.4p1 FreeBSD-20100308
debug1: match: OpenSSH_5.4p1 FreeBSD-20100308 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.8
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 XX
The authenticity of host 'XX' can't be established.
RSA key fingerprint is XX.
Are you sure you want to continue connecting (yes/no)? yes
Failed to add the host to the list of known hosts (/home/XX/.ssh/known_hosts).
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: Trying private key: .ssh/server
debug1: read PEM private key done: type RSA
debug1: Authentications that can continue: publickey,keyboard-interactive
debug1: Next authentication method: keyboard-interactive
Password:


SSH is the latest version available for archlinux

Regards