Укрепление SSH не работает должным образом

Я пытаюсь усилить защиту ssh на своем сервере, но похоже, что это просто блокирует всех. Я проверил auth.log на целевом сервере, и там просто написано: «Соединение закрыто x.x.x.x [preauth]». Позвольте мне вставить сюда sshd_config:

# Package generated configuration file
# See the sshd_config(5) manpage for details    

# What ports, IPs and protocols we listen for
Port 1000
# Use these options to restrict which interfaces/protocols sshd will bind to
#ListenAddress ::
#ListenAddress 0.0.0.0
Protocol 2
# HostKeys for protocol version 2
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_dsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
#Privilege Separation is turned on for security
UsePrivilegeSeparation yes    

# Lifetime and size of ephemeral version 1 server key
KeyRegenerationInterval 3600
ServerKeyBits 768    

# Logging
SyslogFacility AUTH
LogLevel INFO    

# Authentication:
LoginGraceTime 120
PermitRootLogin no
StrictModes yes    

RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile  %h/.ssh/authorized_keys    

# Don't read the user's ~/.rhosts and ~/.shosts files
IgnoreRhosts yes
# For this to work you will also need host keys in /etc/ssh_known_hosts
RhostsRSAAuthentication no
# similar for protocol version 2
HostbasedAuthentication no
# Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication
#IgnoreUserKnownHosts yes    

# To enable empty passwords, change to yes (NOT RECOMMENDED)
PermitEmptyPasswords no    

# Change to yes to enable challenge-response passwords (beware issues with
# some PAM modules and threads)
ChallengeResponseAuthentication no    

# Change to no to disable tunnelled clear text passwords
PasswordAuthentication no    

# Kerberos options
#KerberosAuthentication no
#KerberosGetAFSToken no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes    

# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes    

X11Forwarding yes
X11DisplayOffset 10
PrintMotd no
PrintLastLog yes
TCPKeepAlive yes
#UseLogin no    

#MaxStartups 10:30:60
#Banner /etc/issue.net    

# Allow client to pass locale environment variables
AcceptEnv LANG LC_*    

Subsystem sftp /usr/lib/openssh/sftp-server    

# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the ChallengeResponseAuthentication and
# PasswordAuthentication.  Depending on your PAM configuration,
# PAM authentication via ChallengeResponseAuthentication may bypass
# the setting of "PermitRootLogin without-password".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
UsePAM yes
AllowUsers <myusername>

Я сопоставил свой открытый ключ с файлом authorized_keys в домашнем каталоге имени пользователя на целевом сервере. Что тут может быть не так?

Я пытаюсь сделать ssh вот так:

ssh -p 1000 username@serverhostname

А у меня там все говорят:

Ubuntu 12.04.2 LTS
Permission denied (publickey).