SSH远程登陆配置sshd_config文件详解

# $OpenBSD: sshd_config,v 1.100 2016/08/15 12:32:04 naddy Exp $ # This is the sshd server system-wide configuration file.  See # sshd_config(5) for more information. # This sshd was compiled with PATH=/usr/local/bin:/usr/bin # The strategy used for options in the default sshd_config shipped with # OpenSSH is to specify options with their default value where # possible, but leave them commented.  Uncommented options override the # default value. # If you want to change the port on a SELinux system, you have to tell # SELinux about this change. # semanage port -a -t ssh_port_t -p tcp #PORTNUMBER    <==在开启selinux的系统上，修改ssh端口的要修改selinux规则，用此命令修改 # #Port 22           <==默认ssh端口，生产环境中建议改成五位数的端口  #AddressFamily any   <==地址家族，any表示同时监听ipv4和ipv6地址 #ListenAddress 0.0.0.0  <==监听本机所有ipv4地址 #ListenAddress ::    <==监听本机所有ipv6地址 HostKey /etc/ssh/ssh_host_rsa_key   <==ssh所使用的RSA私钥路径 
#HostKey /etc/ssh/ssh_host_dsa_key HostKey /etc/ssh/ssh_host_ecdsa_key   <==ssh所使用的ECDSA私钥路径 
HostKey /etc/ssh/ssh_host_ed25519_key   <==ssh所使用的ED25519私钥路径 
# Ciphers and keying #RekeyLimit default none # Logging #SyslogFacility AUTH SyslogFacility AUTHPRIV    <==设定在记录来自sshd的消息的时候，是否给出“facility code” 
#LogLevel INFO    <==日志记录级别，默认为info  # Authentication: #LoginGraceTime 2m    <==限定用户认证时间为2min #PermitRootLogin yes   <==是否允许root账户ssh登录，生产环境中建议改成no，使用普通账户ssh登录 #StrictModes yes    <==设置ssh在接收登录请求之前是否检查用户根目录和rhosts文件的权限和所有权，建议开启 #MaxAuthTries 6   <==指定每个连接最大允许的认证次数。默认值是 6 #MaxSessions 10   <==最大允许保持多少个连接。默认值是 10  #PubkeyAuthentication yes  <==是否开启公钥验证 # 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   <==公钥验证文件路径 
#AuthorizedPrincipalsFile none #AuthorizedKeysCommand none #AuthorizedKeysCommandUser nobody # For this to work you will also need host keys in /etc/ssh/ssh_known_hosts #HostbasedAuthentication no # Change to yes if you don't trust ~/.ssh/known_hosts for # HostbasedAuthentication   <==指定服务器在使用 ~/.shosts ~/.rhosts /etc/hosts.equiv 进行远程主机名匹配时，是否进行反向域名查询 #IgnoreUserKnownHosts no  <==是否在 RhostsRSAAuthentication 或 HostbasedAuthentication 过程中忽略用户的 ~/.ssh/known_hosts 文件 # Don't read the user's ~/.rhosts and ~/.shosts files #IgnoreRhosts yes   <==是否在 RhostsRSAAuthentication 或 HostbasedAuthentication 过程中忽略 .rhosts 和 .shosts 文件 # To disable tunneled clear text passwords, change to no here! #PasswordAuthentication yes #PermitEmptyPasswords no    <==是否允许空密码 PasswordAuthentication yes   <==是否允许密码验证，生产环境中建议改成no，只用密钥登录 
# Change to no to disable s/key passwords #ChallengeResponseAuthentication yes ChallengeResponseAuthentication no   <==是否允许质疑-应答(challenge-response)认证 
# Kerberos options #KerberosAuthentication no   <==是否使用Kerberos认证 #KerberosOrLocalPasswd yes   <==如果 Kerberos 密码认证失败，那么该密码还将要通过其它的认证机制(比如 /etc/passwd) #KerberosTicketCleanup yes  <==是否在用户退出登录后自动销毁用户的 ticket #KerberosGetAFSToken no  <==如果使用了AFS并且该用户有一个 Kerberos 5 TGT，那么开启该指令后，将会在访问用户的家目录前尝试获取一个AFS token #KerberosUseKuserok yes # GSSAPI options GSSAPIAuthentication yes   <==是否允许基于GSSAPI的用户认证 
GSSAPICleanupCredentials no    <==是否在用户退出登录后自动销毁用户凭证缓存 
#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   <==是否通过PAM验证 
#AllowAgentForwarding yes #AllowTcpForwarding yes #GatewayPorts no     <==是否允许远程主机连接本地的转发端口 X11Forwarding yes    <==是否允许X11转发 
#X11DisplayOffset 10  <==指定sshd（8）X11转发的第一个可用的显示区(display)数字。默认值是10 #X11UseLocalhost yes  <==是否应当将X11转发服务器绑定到本地loopback地址 #PermitTTY yes #PrintMotd yes     <==指定sshd(8)是否在每一次交互式登录时打印 /etc/motd 文件的内容 #PrintLastLog yes  <==指定sshd(8)是否在每一次交互式登录时打印最后一位用户的登录时间 #TCPKeepAlive yes  <==指定系统是否向客户端发送 TCP keepalive 消息 #UseLogin no   <==是否在交互式会话的登录过程中使用 login（1） #UsePrivilegeSeparation sandbox  <==是否让 sshd(8) 通过创建非特权子进程处理接入请求的方法来进行权限分离 #PermitUserEnvironment no  <==指定是否允许sshd(8)处理~/.ssh/environment以及 ~/.ssh/authorized_keys中的 environment= 选项 #Compression delayed  <==是否对通信数据进行加密，还是延迟到认证成功之后再对通信数据加密 #ClientAliveInterval 0  <==sshd(8)长时间没有收到客户端的任何数据，不发送"alive"消息 #ClientAliveCountMax 3   <==sshd(8)在未收到任何客户端回应前最多允许发送多个"alive"消息，默认值是 3  #ShowPatchLevel no #UseDNS no      <==是否使用dns反向解析 #PidFile /var/run/sshd.pid   <==指定存放SSH守护进程的进程号的路径 #MaxStartups 10:30:100   <==最大允许保持多少个未认证的连接 #PermitTunnel no   <==是否允许tun(4)设备转发 #ChrootDirectory none #VersionAddendum none # no default banner path #Banner none  <==将这个指令指定的文件中的内容在用户进行认证前显示给远程用户，默认什么内容也不显示，"none"表示禁用这个特性 # 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   <==配置一个外部子系统sftp及其路径 
# Example of overriding settings on a per-user basis #Match User anoncvs    <==引入一个条件块。块的结尾标志是另一个 Match 指令或者文件结尾     #       X11Forwarding no #       AllowTcpForwarding no #       PermitTTY no #       ForceCommand cvs server

/bin/systemctl start sshd.service