0403随堂笔记

Linux随堂笔记window 终端工具使用秘钥登录Linux生成密钥对私钥和公钥将公钥复制给Linux服务器测试一 生成密钥对私钥和公钥1.xshell 为例 工具-用户秘钥管理者-生成打开界面基本上是下一步即可。找到私钥-属性-公钥标签复制公钥。例如ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA5iehrGHGRDds6KIQkekDN6Fa1xsyV6DNgQRIfQYzGraO7c2XGu03CtdoCHWOpaJeGpjUqPdrA8vlEV9AfgaIZVTrLBuWqNRjtipFgrLrvnX36YqPBVJfN/Jq9YV0pI8w1bIcHNeRSY/6Asji9O4YouzQGZ5fcKumdcr0DO6kddvgBKgwACVgaF1Rnpg6jUBKpWMoie7QMB4iMIxpRkp1L96xSnWvXaPxMN94QYH/n2hn971MpT0sIXM3g0qf9VDgz5vAx3ED2GlME1b3AmKaJ270fRJSugh1MfS9Z/uUN5pOmJJ1YU6Vh4oB/fAaLudHqZAFQK38kFtJqYw rsa 2048-202604032.写入对方文件进入普通用户家目录下的.ssh目录下,创建authorized_keys文件并将上述公钥写入[liangCentOS7 .ssh 19:40:26]$ touch authorized_keys[liangCentOS7 .ssh 19:42:11]$ vim authorized_keys.验证结果[liangCentOS7 .ssh 19:43:52]$ cat authorized_keysssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA5iehrGHGRDds6KIQkekDN6Fa1xsyV6DNgQRIfQYzGraO7c2XGu03CtdoCHWOpaJeGpjUqPdrA8vlEV9AfgaIZVTrLBuWqNRjtipFgrLrvnX36YqPBVJfN/Jq9YV0pI8w1bIcHNeRSY/6Asji9O4YouzQGZ5fcKumdcr0DO6kddvgBKgwACVgaF1Rnpg6jUBKpWMoie7QMB4iMIxpRkp1L96xSnWvXaPxMN94QYH/n2hn971MpT0sIXM3g0qf9VDgz5vAx3ED2GlME1b3AmKaJ270fRJSugh1MfS9Z/uUN5pOmJJ1YU6Vh4oB/fAaLudHqZAFQK38kFtJqYw rsa 2048-2026040观察可知写入成功。3 查看ssh文件及目录的权限[liangCentOS7 .ssh 19:46:04]$ ls -ltotal 4-rw-rw-r-- 1 liang liang 399 Apr 5 19:43 authorized_keys[liangCentOS7 ~ 21:12:04]$ ll -atotal 484drwx------. 4 liang liang 170 Apr 5 21:04 .drwxr-xr-x. 3 root root 19 Apr 3 14:17 …-rw-------. 1 liang liang 709 Apr 5 20:10 .bash_history-rw-r–r–. 1 liang liang 18 Nov 25 2021 .bash_logout-rw-r–r–. 1 liang liang 193 Nov 25 2021 .bash_profile-rw-r–r–. 1 liang liang 231 Nov 25 2021 .bashrcdrwxrwxr-x 3 liang liang 17 Apr 5 20:26 etc-rw-rw-r-- 1 liang liang 470524 Aug 8 2023 openssh-server-7.4p1-23.el7_9.x86_64.rpmdrwxrwxr-x 2 liang liang 29 Apr 5 21:04 .ssh-rw------- 1 liang liang 4625 Apr 5 21:04 .viminfo根据以上返回结果可知authorized_keys权限为664.ssh目录权限为775不符合ssh服务要求应将authorized_keys权限改为600.ssh目录权限改为700操作如下liangCentOS7 ~ 21:12:06]$ chmod 700 .ssh[liangCentOS7 .ssh 21:04:24]$ chmod 600 authorized_keys·4 登录时候选择验证方式公钥并指定对应公钥刚刚实现 windows 使用 laoma 用户秘钥登录 centos7思考如何实现 windows 使用 root 用户秘钥登录 centos7[rootcentos7 ~ 10:19:01]# cat /home/liang/.ssh/authorized_keys /root/.ssh/authorized_keysssh 工具配置文件指令解释~/.ssh/config用户级别给用户自己定制优先级更高/etc/ssh/ssh_config系统全局级别默认设置针对系统中所有用户生效sshd 服务配置文件/etc/ssh/sshd_config针对sshd服务生效。 man 帮助 man 帮助命令 --help 查询命令如果查询配置文件如何写man 配置文件名例如man sshd_config搜索 Root/Root 软件包升级 查询软件包版本[rootCentOS7 ~ 19:44:59]# rpm -q openssh-serveropenssh-server-7.4p1-23.el7_9.x86_64查询可用版本升级到最新版本测试 参数 /etc/ssh/sshd_config 中参数 PermitRootLogin prohibit-password 软件包升级 vmware 三种网络模式桥接模式Bridged虚拟机就像家里又多了一台独立电脑和你本机平起平坐。它有自己的 IP跟你本机在同一个局域网别人能直接访问它它也能直接访问别人就像你多插了一根网线给虚拟机解释就是虚拟机是局域网里的一台真实电脑NAT 模式 虚拟机共享你本机的网络出门外面看不见它。虚拟机可以上网、访问你本机但局域网里别的电脑找不到它就像你本机开了个热点虚拟机连热点上网解释虚拟机躲在你电脑后面上网而且只进不出仅主机模式Host-Only 虚拟机和你本机关在一个小房间里不连外面的网只能和你本机互相访问不能上互联网也不能访问局域网其他设备纯内部局域网与世隔绝解释虚拟机和本机私下玩耍不连外网指令解释bash-completion 命令行补全vim 高亮显示编辑器open-vm-tools vmware 更好地控制虚拟机lrzsz 上传和下载unzip 解压ziprsync 同步sshpass 传递密码日志管理systemd-journal systemd子系统rsyslog 服务对应rsyslog 将日志记录到对应的文件中| /var/log/messages | 大多数系统日志排除认证、邮件、定时任务、调试日志 || /var/log/secure | 安全/认证相关日志如ssh登录、用户验证 || /var/log/maillog | 邮件服务相关日志如sendmail/postfix || /var/log/cron | 定时任务执行日志crontab/anacron || /var/log/boot.log | 系统启动过程中的非syslog控制台消息 |人为模拟故障并排故。模拟一[rootCentOS7 .ssh 21:06:53]# echo ‘Hello World’ /etc/ssh/sshd_config刷新sshd服务[rootCentOS7 .ssh 21:38:30]# systemctl restart sshd发现问题Job for sshd.service failed because the control process exited with error code. See “systemctl status sshd.service” and “journalctl -xe” for details.排除故障查看日志[rootCentOS7 .ssh 21:38:51]# tail /var/log/messagesApr 5 21:40:15 CentOS7 systemd: sshd.service failed.Apr 5 21:40:57 CentOS7 systemd: sshd.service holdoff time over, scheduling restart.Apr 5 21:40:57 CentOS7 systemd: Stopped OpenSSH server daemon.Apr 5 21:40:57 CentOS7 systemd: Starting OpenSSH server daemon…Apr 5 21:40:57 CentOS7 sshd: /etc/ssh/sshd_config: line 141: Bad configuration option: HelloApr 5 21:40:57 CentOS7 sshd: /etc/ssh/sshd_config: terminating, 1 bad configuration optionsApr 5 21:40:57 CentOS7 systemd: sshd.service: main process exited, codeexited, status255/n/aApr 5 21:40:57 CentOS7 systemd: Failed to start OpenSSH server daemon.Apr 5 21:40:57 CentOS7 systemd: Unit sshd.service entered failed state.Apr 5 21:40:57 CentOS7 systemd: sshd.service failed.分析结果关注到内容如下Apr 5 21:40:57 CentOS7 sshd: /etc/ssh/sshd_config: terminating, 1 bad configuration options提示我们此处有一个错误的配置选项修复故障 vim进入/etc/ssh/sshd_config删除hello world[rootCentOS7 .ssh 21:41:35]# vim /etc/ssh/sshd_config重启sshd之后查看状态systemctl restart sshdsystemctl status sshdsshd status应有如下返回结果sshd.service - OpenSSH server daemonLoaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)Active: active (running) since Sun 2026-04-05 21:48:49 CST; 10s agoDocs: man:sshd(8)man:sshd_config(5)Process: 1928 ExecReload/bin/kill -HUP $MAINPID (codeexited, status0/SUCCESS)Main PID: 12068 (sshd)CGroup: /system.slice/sshd.service└─12068 /usr/sbin/sshd -DApr 05 21:48:49 CentOS7.liang.cloud systemd[1]: Starting OpenSSH server daem…Apr 05 21:48:49 CentOS7.liang.cloud sshd[12068]: Server listening on 0.0.0.0…Apr 05 21:48:49 CentOS7.liang.cloud sshd[12068]: Server listening on :: port 22.Apr 05 21:48:49 CentOS7.liang.cloud systemd[1]: Started OpenSSH server daemon.Hint: Some lines were ellipsized, use -l to show in full.我们能查看到 Active: active (running)故障修复成功模拟二[rootCentOS7 .ssh 21:49:00]# rm -rf /etc/ssh/sshd_config重启sshd服务及故障显示[rootCentOS7 .ssh 21:55:04]# systemctl restart sshdJob for sshd.service failed because the control process exited with error code. See “systemctl status sshd.service” and “journalctl -xe” for details查看日志结果[rootCentOS7 .ssh 21:57:08]# tail /var/log/messagesApr 5 21:56:56 CentOS7 systemd: Unit sshd.service entered failed state.Apr 5 21:56:56 CentOS7 systemd: sshd.service failed.Apr 5 21:57:38 CentOS7 systemd: sshd.service holdoff time over, scheduling restart.Apr 5 21:57:38 CentOS7 systemd: Stopped OpenSSH server daemon.Apr 5 21:57:38 CentOS7 systemd: Starting OpenSSH server daemon…Apr 5 21:57:38 CentOS7 sshd: /etc/ssh/sshd_config: No such file or directoryApr 5 21:57:38 CentOS7 systemd: sshd.service: main process exited, codeexited, status1/FAILUREApr 5 21:57:38 CentOS7 systemd: Failed to start OpenSSH server daemon.Apr 5 21:57:38 CentOS7 systemd: Unit sshd.service entered failed state.Apr 5 21:57:38 CentOS7 systemd: sshd.service failed.该内容提示我们Apr 5 21:57:38 CentOS7 sshd: /etc/ssh/sshd_config: No such file or directory没有此文件所以我们需要创建一个对应文件具体操作如下[rootCentOS7 .ssh 21:58:15]# yum provides /etc/ssh/sshd_configLoaded plugins: fastestmirrorLoading mirror speeds from cached hostfilebase: mirrors.aliyun.comextras: mirrors.aliyun.comupdates: mirrors.aliyun.comopenssh-server-7.4p1-21.el7.x86_64 : An open source SSH server daemonRepo : baseMatched from:Filename : /etc/ssh/sshd_configopenssh-server-7.4p1-22.el7_9.x86_64 : An open source SSH server daemonRepo : updatesMatched from:Filename : /etc/ssh/sshd_configopenssh-server-7.4p1-23.el7_9.x86_64 : An open source SSH server daemonRepo : updatesMatched from:Filename : /etc/ssh/sshd_configopenssh-server-7.4p1-23.el7_9.x86_64 : An open source SSH server daemonRepo : updatesMatched from:Filename : /etc/ssh/sshd_config下载openssh-server软件包[rootCentOS7 .ssh 22:01:43]# yumdownloader openssh-server操作结果Loaded plugins: fastestmirrorLoading mirror speeds from cached hostfilebase: mirrors.aliyun.comextras: mirrors.aliyun.comupdates: mirrors.aliyun.comopenssh-server-7.4p1-23.el7_9. FAILEDhttp://mirrors.aliyun.com/centos/7/updates/x86_64/Packages/openssh-server-7.4p1-23.el7_9.x86_64.rpm: [Errno 14] curl#7 - “Failed connect to mirrors.aliyun.com:80; Operation now in progress”Trying other mirror.openssh-server-7.4p1-23.el7_9. FAILEDhttp://mirrors.aliyuncs.com/centos/7/updates/x86_64/Packages/openssh-server-7.4p1-23.el7_9.x86_64.rpm: [Errno 14] HTTP Error 404 - Not FoundTrying other mirror.To address this issue please refer to the below wiki articlehttps://wiki.centos.org/yum-errorsIf above article doesn’t help to resolve this issue please use https://bugs.centos.org/.openssh-server-7.4p1-23.el7_9. FAILEDhttp://mirrors.cloud.aliyuncs.com/centos/7/updates/x86_64/Packages/openssh-server-7.4p1-23.el7_9.x86_64.rpm: [Errno 14] curl#7 - “Failed connect to mirrors.cloud.aliyuncs.com:80; Connection refused”Trying other mirror.openssh-server-7.4p1-23.el7_9.x86_64.rpm查看软件包中的文件[rootCentOS7 .ssh 22:04:29]# rpm2cpio openssh-server-7.4p1-23.el7_9.x86_64.rpm | cpio -t得出如下反馈结果./etc/pam.d/sshd./etc/ssh/sshd_config./etc/sysconfig/sshd./usr/lib/systemd/system/sshd-keygen.service./usr/lib/systemd/system/sshd.service./usr/lib/systemd/system/sshd.socket./usr/lib/systemd/system/sshd.service./usr/lib64/fipscheck/sshd.hmac./usr/libexec/openssh/sftp-server./usr/sbin/sshd./usr/sbin/sshd-keygen./usr/share/man/man5/moduli.5.gz./usr/share/man/man5/sshd_config.5.gz./usr/share/man/man8/sftp-server.8.gz./usr/share/man/man8/sshd.8.gz./var/empty/sshd1946 blocks提取对应文件[rootCentOS7 .ssh 22:06:33]# rpm2cpio openssh-server-7.4p1-23.el7_9.x86_64.rpm | cpio -id ./etc/ssh/sshd_config1946 blocks查看是否操作成功[rootCentOS7 .ssh 22:08:51]# tree etcetc└── ssh└── sshd_config1 directory, 1 file将下载文件放置到对应位置[rootCentOS7 .ssh 22:10:05]# mv ./etc/ssh/sshd_config /etc/ssh/sshd_config重启sshd服务并查看状态[rootCentOS7 .ssh 22:12:02]# systemctl restart sshd[rootCentOS7 .ssh 22:12:54]# systemctl status sshdsshd status应有如下返回结果● sshd.service - OpenSSH server daemonLoaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)Active: active (running) since Sun 2026-04-05 22:12:54 CST; 10s agoDocs: man:sshd(8)man:sshd_config(5)Process: 1928 ExecReload/bin/kill -HUP $MAINPID (codeexited, status0/SUCCESS)Main PID: 12213 (sshd)CGroup: /system.slice/sshd.service└─12213 /usr/sbin/sshd -DApr 05 22:12:54 CentOS7.liang.cloud systemd[1]: Starting OpenSSH server daem…Apr 05 22:12:54 CentOS7.liang.cloud sshd[12213]: Server listening on 0.0.0.0…Apr 05 22:12:54 CentOS7.liang.cloud sshd[12213]: Server listening on :: port 22.Apr 05 22:12:54 CentOS7.liang.cloud systemd[1]: Started OpenSSH server daemon.Hint: Some lines were ellipsized, use -l to show in full.观察结果为Active: active (running) since Sun 2026-04-05 22:12:54 CST; 10s ago故障修复成功