#Port 22 监听端口，默认监听22端口 【默认可修改】

#AddressFamily any IPV4和IPV6协议家族用哪个，any表示二者均有

#ListenAddress 0.0.0.0 指明监控的地址，0.0.0.0表示本机的所有地址 【默认可修改】

#ListenAddress :: 指明监听的IPV6的所有地址格式

The default requires explicit activation of protocol 1

#Protocol 2 使用SSH第二版本，centos7默认第一版本已拒绝

HostKey for protocol version 1 一版的SSH支持以下一种秘钥形式

#HostKey /etc/ssh/ssh_host_key

HostKeys for protocol version 2 使用第二版本发送秘钥，支持以下四种秘钥认证的存放位置：（centos6只支持rsa和dsa两种）

HostKey /etc/ssh/ssh_host_rsa_key rsa私钥认证 【默认】

#HostKey /etc/ssh/ssh_host_dsa_key dsa私钥认证

HostKey /etc/ssh/ssh_host_ecdsa_key ecdsa私钥认证

HostKey /etc/ssh/ssh_host_ed25519_key ed25519私钥认证

Lifetime and size of ephemeral version 1 server key

#KeyRegenerationInterval 1h

#ServerKeyBits 1024 主机秘钥长度

Ciphers and keying

#RekeyLimit default none

Logging

obsoletes QuietMode and FascistLogging

#SyslogFacility AUTH

SyslogFacility AUTHPRIV 当有人使用ssh登录系统的时候，SSH会记录信息，信息保存在/var/log/secure里面

#LogLevel INFO 日志的等级

Authentication:

#LoginGraceTime 2m 登录的宽限时间，默认2分钟没有输入密码，则自动断开连接

#PermitRootLogin no

PermitRootLogin yes 是否允许管理员直接登录，‘yes‘表示允许

#StrictModes yes 是否让sshd去检查用户主目录或相关文件的权限数据

#MaxAuthTries 6 最大认证尝试次数，最多可以尝试6次输入密码。之后需要等待某段时间后才能再次输入密码

#MaxSessions 10 允许的最大会话数

#RSAAuthentication yes

#PubkeyAuthentication yes

The default is to check both .ssh/authorized_keys and .ssh/authorized_keys2

but this is overridden so installations will only check .ssh/authorized_keys

AuthorizedKeysFile .ssh/authorized_keys 服务器生成一对公私钥之后，会将公钥放到.ssh/authorizd_keys里面，将私钥发给客户端

#AuthorizedPrincipalsFile none

#AuthorizedKeysCommand none

#AuthorizedKeysCommandUser nobody

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 yes

#PermitEmptyPasswords no

PasswordAuthentication yes 是否允许支持基于口令的认证

Change to no to disable s/key passwords

#ChallengeResponseAuthentication yes

ChallengeResponseAuthentication no 是否允许任何的密码认证

Kerberos options 是否支持kerberos（基于第三方的认证，如LDAP）认证的方式，默认为no

#KerberosAuthentication no

#KerberosOrLocalPasswd yes

#KerberosTicketCleanup yes

#KerberosGetAFSToken no

#KerberosUseKuserok yes

GSSAPI options

GSSAPIAuthentication yes

GSSAPICleanupCredentials no

#GSSAPIStrictAcceptorCheck yes

#GSSAPIKeyExchange no

#GSSAPIEnablek5users no

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‘.

WARNING: ‘UsePAM no‘ is not supported in Red Hat Enterprise Linux and may cause several

problems.

UsePAM yes

#AllowAgentForwarding yes

#AllowTcpForwarding yes

#GatewayPorts no

X11Forwarding yes 是否允许x11转发，可以让窗口的数据通过SSH连接来传递(请查看ssh -X 参数)：#ssh -X user@IP

#X11DisplayOffset 10

#X11UseLocalhost yes

#PermitTTY yes

#PrintMotd yes

#PrintLastLog yes

#TCPKeepAlive yes

#UseLogin no

UsePrivilegeSeparation sandbox # Default for new installations.

#PermitUserEnvironment no

#Compression delayed

#ClientAliveInterval 0

#ClientAliveCountMax 3

#ShowPatchLevel no

#UseDNS yes 是否反解DNS，如果想让客户端连接服务器端快一些，这个可以改为no

#PidFile /var/run/sshd.pid

#MaxStartups 10:30:100

#PermitTunnel no

#ChrootDirectory none

#VersionAddendum none

no default banner path

#Banner none

Accept locale-related environment variables

AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES

AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT

AcceptEnv LC_IDENTIFICATION LC_ALL LANGUAGE

AcceptEnv XMODIFIERS

override default of no subsystems

Subsystem sftp /usr/libexec/openssh/sftp-server 支持 SFTP ，如果注释掉，则不支持sftp连接

Example of overriding settings on a per-user basis

#Match User anoncvs

X11Forwarding no

AllowTcpForwarding no

PermitTTY no

ForceCommand cvs server

AllowUsers user1 user2 登录白名单（默认没有这个配置，需要自己手动添加），允许远程登录的用户。如果名单中没有的用户，则提示拒绝登录