putty

Тебе надо не ssh_config, а sshd_config

#Port 22
Protocol 2
#AddressFamily any
ListenAddress your_ip
#ListenAddress ::

# HostKey for protocol version 1
# HostKey /etc/ssh/ssh_host_key
# HostKeys for protocol version 2
# HostKey /etc/ssh/ssh_host_rsa_key
# HostKey /etc/ssh/ssh_host_dsa_key

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

# Logging
# obsoletes QuietMode and FascistLogging
# SyslogFacility AUTH
# LogLevel INFO

# Authentication:

# LoginGraceTime 2m
PermitRootLogin yes
# StrictModes yes
# MaxAuthTries 6
# RSAAuthentication yes
# PubkeyAuthentication yes
# AuthorizedKeysFile .ssh/authorized_keys
# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
# RhostsRSAAuthentication no
# similar for protocol version 2
# HostbasedAuthentication no
# Change to yes if you don't trust ~/.ssh/known_hosts for
# RhostsRSAAuthentication and HostbasedAuthentication
# IgnoreUserKnownHosts no
# Don't read the user's ~/.rhosts and ~/.shosts files
# IgnoreRhosts yes

# To disable tunneled clear text passwords, change to no here!
PasswordAuthentication no
# PermitEmptyPasswords no

# Change to no to disable s/key passwords
# ChallengeResponseAuthentication yes

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

# GSSAPI options
# GSSAPIAuthentication no
# GSSAPICleanupCredentials yes

# 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 mechanism.
# Depending on your PAM configuration, this may bypass the setting of
# PasswordAuthentication, PermitEmptyPasswords, and
# "PermitRootLogin without-password". If you just want the PAM account and
# session checks to run without PAM authentication, then enable this but set
# ChallengeResponseAuthentication=no
UsePAM yes