1 Qomo Linux 简介
2 新手指南
2.1 前言
2.2 准备
2.3 安装
2.4 适配
2.5 使用
3 安装手册
3.1 安装总览
3.2 获取Qomo
3.3 硬盘安装
3.4 LiveCD/DVD试用
3.5 LiveCD/DVD安装
3.6 U盘安装
3.7 虚拟机安装
3.8 双系统
3.9 网络安装
4 用户手册
4.1 Qomo 1.1用户手册
4.2 使用DOSBox
4.3 桌面应用程序
4.4 Windows应用移植
4.5 文件和资源管理(P22)
4.6 系统和桌面设置(SP2)
4.7 术语表
5 开发手册
5.1 命令行
5.1.1 Shell简介
5.1.2 Shell编程基础
5.1.3 如何进入命令行界面
5.1.4 改变登录方式
5.1.5 Vim
5.1.6 FTP
5.1.7 RPM
5.1.8 Telnet
5.1.9 安装应用软件
5.1.10 常用文件系统管理命令
5.1.11 文件系统
5.1.12 管道
5.1.13 维护文件系统
5.2 KDE
5.2.1 KDE加速
5.3 SSH
5.4 Git
5.4.1 起步
5.4.2 基础
5.4.3 分支
5.4.4 服务器上的 Git
5.4.5 分布式 git(上)
5.4.6 分布式 git(下)
5.4.7 git 工具(上)
5.4.8 git 工具(下)
5.4.9 自定义 git(上)
5.4.10 自定义 git(下)
5.4.11 git 与其它系统
5.4.12 git 内部原理(上)
5.4.13 git 内部原理(下)
5.4.14 Git简易教程
5.5 其他
5.5.1 Bash
6 历史版本
6.1 Qomo Linux 0.7
6.2 Qomo Linux 0.8
6.3 Qomo Linux 1.0
6.4 Qomo Linux 1.1.0
6.5 Qomo Linux 1.2.0
6.6 Qomo Linux 2.0
6.7 Qomo Linux 3.0
6.8 Qomo Linux 3.1
6.9 Qomo Linux 4.0 Beta
6.10 Qomo Linux 4.0
6.11 Qomo Linux 4.1
6.12 Qomo Linux 4.2圣诞版
6.13 Qomo Linux 4.5
6.14 Qomo Linux 4.8七夕版(增加了64位版)

SSH

2016-11-14 21:26:20
Cacricornus
514
最后编辑:Cacricornus 于 2016-11-16 21:30:31


SSH

Secure Shell(SSH)是一个允许两台电脑之间通过安全的连接进行数据交换的网络协议。加密技术保证了数据的保密性和完整性。如果有必要的话,SSH采用公匙加密技术来验证远程主机,以及必要时允许远程主机验证用户。


SSH 通常用于远程访问和执行命令,但是它也支持隧道,转发任意 TCP 端口以及 X11 连接;它还能够用 SFTP 或 SCP 协议来传递文件。

一个 SSH 服务器,默认地,在 TCP 端口 22 进行监听。一个 SSH 客户端程序通常被用来建立一个接受远程连接的 sshd 守护进程。这两者都以专利的,自由软件的以及开源版本的形式和不同的复杂性和完整性,被广泛地应用在现代的操作系统中,包括 Mac OS X,GNU/Linux,Solaris 和 OpenVMS 等。




OpenSSH

OpenSSH (OpenBSD Secure Shell) 是一套用ssh协议,通过电脑网络,提供加密通讯会话的电脑程序。它相对于SSH Communications Security公司拥有专利的Secure Shell软件套装,被创建为开源。OpenSSH是由Theo de Raadt领导的OpenBSD项目的一部分。

人们常把OpenSSH与相似的OpenSSL搞混,但是,这两个项目是由不同的团队开发出来的,有不同的用途,相似的名字只是由于相似的目标。


安装OpenSSH


sudo yum install openssh


配置SSH

客户端

SSH客户端的配置文件是/etc/ssh/ssh_config。

以下是一个范例::

文件: /etc/ssh/ssh_config

<pre<noinclude></noinclude> style="padding: 0.25em; margin: 0 0 0.50em 0; background-color: #F7F7F7; border: thin dashed #7F7F7F; border-top: none"># $OpenBSD: ssh_config,v 1.26 2010/01/11 01:39:46 dtucker Exp $

  1. This is the ssh client system-wide configuration file. See
  2. ssh_config(5) for more information. This file provides defaults for
  3. users, and the values can be changed in per-user configuration files
  4. or on the command line.
  1. Configuration data is parsed as follows:
  2. 1. command line options
  3. 2. user-specific file
  4. 3. system-wide file
  5. Any configuration value is only changed the first time it is set.
  6. Thus, host-specific definitions should be at the beginning of the
  7. configuration file, and defaults at the end.
  1. Site-wide defaults for some commonly used options. For a comprehensive
  2. list of available options, their meanings and defaults, please see the
  3. ssh_config(5) man page.
  1. Host *
  2. ForwardAgent no
  3. ForwardX11 no
  4. RhostsRSAAuthentication no
  5. RSAAuthentication yes
  6. PasswordAuthentication yes
  7. HostbasedAuthentication no
  8. GSSAPIAuthentication no
  9. GSSAPIDelegateCredentials no
  10. BatchMode no
  11. CheckHostIP yes
  12. AddressFamily any
  13. ConnectTimeout 0
  14. StrictHostKeyChecking ask
  15. IdentityFile ~/.ssh/identity
  16. IdentityFile ~/.ssh/id_rsa
  17. IdentityFile ~/.ssh/id_dsa
  18. Port 22
  19. Protocol 2,1
  20. Cipher 3des
  21. Ciphers aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc
  22. MACs hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160
  23. EscapeChar ~
  24. Tunnel no
  25. TunnelDevice any:any
  26. PermitLocalCommand no
  27. VisualHostKey no
  28. ProxyCommand ssh -q -W %h:%p gateway.example.com</pre<noinclude></noinclude>>

推荐将“Protocol”行改为:

Protocol 2


这表示只有协议2将被用到,因为协议1 被认为不太安全。

守护进程

SSH客户端的配置文件是/etc/ssh/sshd_config。

以下是一个范例::

文件: /etc/ssh/sshd_config

<pre<noinclude></noinclude> style="padding: 0.25em; margin: 0 0 0.50em 0; background-color: #F7F7F7; border: thin dashed #7F7F7F; border-top: none"># $OpenBSD: sshd_config,v 1.82 2010/09/06 17:10:19 naddy Exp $

  1. This is the sshd server system-wide configuration file. See
  2. sshd_config(5) for more information.
  1. This sshd was compiled with PATH=/usr/bin:/bin:/usr/sbin:/sbin
  1. The strategy used for options in the default sshd_config shipped with
  2. OpenSSH is to specify options with their default value where
  3. possible, but leave them commented. Uncommented options change a
  4. default value.
  1. Port 22
  2. AddressFamily any
  3. ListenAddress 0.0.0.0
  4. ListenAddress ::
  1. The default requires explicit activation of protocol 1
  2. Protocol 2
  1. HostKey for protocol version 1
  2. HostKey /etc/ssh/ssh_host_key
  3. HostKeys for protocol version 2
  4. HostKey /etc/ssh/ssh_host_rsa_key
  5. HostKey /etc/ssh/ssh_host_dsa_key
  6. HostKey /etc/ssh/ssh_host_ecdsa_key
  1. Lifetime and size of ephemeral version 1 server key
  2. KeyRegenerationInterval 1h
  3. ServerKeyBits 1024
  1. Logging
  2. obsoletes QuietMode and FascistLogging
  3. SyslogFacility AUTH
  4. LogLevel INFO
  1. Authentication:
  1. LoginGraceTime 2m
  2. PermitRootLogin yes
  3. StrictModes yes
  4. MaxAuthTries 6
  5. MaxSessions 10
  1. RSAAuthentication yes
  2. PubkeyAuthentication yes
  3. AuthorizedKeysFile .ssh/authorized_keys
  1. For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
  2. RhostsRSAAuthentication no
  3. similar for protocol version 2
  4. HostbasedAuthentication no
  5. Change to yes if you don't trust ~/.ssh/known_hosts for
  6. RhostsRSAAuthentication and HostbasedAuthentication
  7. IgnoreUserKnownHosts no
  8. Don't read the user's ~/.rhosts and ~/.shosts files
  9. IgnoreRhosts yes
  1. To disable tunneled clear text passwords, change to no here!
  2. PasswordAuthentication yes
  3. PermitEmptyPasswords no
  1. Change to no to disable s/key passwords

ChallengeResponseAuthentication no

  1. Kerberos options
  2. KerberosAuthentication no
  3. KerberosOrLocalPasswd yes
  4. KerberosTicketCleanup yes
  5. KerberosGetAFSToken no
  1. GSSAPI options
  2. GSSAPIAuthentication no
  3. GSSAPICleanupCredentials yes
  1. Set this to 'yes' to enable PAM authentication, account processing,
  2. and session processing. If this is enabled, PAM authentication will
  3. be allowed through the ChallengeResponseAuthentication and
  4. PasswordAuthentication. Depending on your PAM configuration,
  5. PAM authentication via ChallengeResponseAuthentication may bypass
  6. the setting of "PermitRootLogin without-password".
  7. If you just want the PAM account and session checks to run without
  8. PAM authentication, then enable this but set PasswordAuthentication
  9. and ChallengeResponseAuthentication to 'no'.

UsePAM yes

  1. AllowAgentForwarding yes
  2. AllowTcpForwarding yes
  3. GatewayPorts no
  4. X11Forwarding no
  5. X11DisplayOffset 10
  6. X11UseLocalhost yes
  7. PrintMotd yes
  8. PrintLastLog yes
  9. TCPKeepAlive yes
  10. UseLogin no
  11. UsePrivilegeSeparation yes
  12. PermitUserEnvironment no
  13. Compression delayed
  14. ClientAliveInterval 0
  15. ClientAliveCountMax 3
  16. UseDNS yes
  17. PidFile /var/run/sshd.pid
  18. MaxStartups 10
  19. PermitTunnel no
  20. ChrootDirectory none
  1. no default banner path
  2. Banner none
  1. override default of no subsystems

Subsystem sftp /usr/lib/ssh/sftp-server

  1. Example of overriding settings on a per-user basis
  2. Match User anoncvs
  3. X11Forwarding no
  4. AllowTcpForwarding no
  5. ForceCommand cvs server</pre<noinclude></noinclude>>

只允许某些用户访问的话,加入这一行:

AllowUsers user1 user2


要禁止通过SSH进行root用户登录,加入以下行:

PermitRootLogin no


你也可以取消BANNER选项的注释,然后编辑/etc/issue加入友好的欢迎信息内容。

提示: 你可能想要把默认的端口从22改成其它更高的端口(参考 security through obscurity).

尽管ssh的运行端口可以被像nmap这样的端口扫描器侦测到,但改变它可以减少由于自动验证的尝试造成登录次数。

提示: 完全取消密码登录方式也可以增强安全性,因为每个访问服务器的用户都需要创建ssh密钥。.
文件: /etc/ssh/sshd_config

<pre<noinclude></noinclude> style="padding: 0.25em; margin: 0 0 0.50em 0; background-color: #F7F7F7; border: thin dashed #7F7F7F; border-top: none">PasswordAuthentication no ChallengeResponseAuthentication no</pre<noinclude></noinclude>>

管理SSHD守护进程

只要把sshd加到/etc/rc.conf中的"DAEMONS" section部分:


DAEMONS=(... ...sshd... ...)
开始/重启/停止这个daemon:
# rc.d {start|stop|restart} sshd


连接到服务器

运行下面的命令:

$ ssh -p port user@server-address


小细节和小戏法

加密Socks通道

对于连接到各种不安全的无线网络上的笔记本电脑用户来说,这个是特别有用的!唯一所需要的就是一个一定程度上处于安全的地点的SSH服务器,比如在家里或办公室。用动态的DNS服务DynDNS也可能是很有用的,这样你就不必记住你的IP了。

第一步:开始连接

你只要在你喜欢的终端中执行这一个命令就能开始你的连接:


$ ssh -ND 4711 user@host
这里的“user”是你在“host”这台SSH服务器上运行的用户名。它会让你输入密码,然后你就能连上了。“N”表示不采用交互提示,而“D”表示指定监听的本地端口(你可以使用任何你喜欢的数字)


一个办法可以让这个过程更简单,那就是在~/.bashrc中加入这样一行:


alias sshtunnel="ssh -ND 4711 -v user@host"
加入冗长的“-v”标志更好,因为这样你可以验证是真的是从那个端口连接的。现在你只要执行命令“sshtunnel”就可以。 :)


第二步:配置你的浏览器(或其它程序)

如果你不配置你的web浏览器以便使用新创建的socks通道的话,上面的一步完全没用!

  • 对于Firefox: Edit -> Preferences -> Advanced -> Network -> Connection -> Setting:
检查"Manual proxy configuration" radio button?, 并且在"SOCKS host" 文本段输入"localhost" , 然后在接下来的一个文本框中输入你的端口数(上面我们用的是4711)。确定你选择使用SOCKS4。这个程序对不会对SOCKS5起作用.享受你的安全通道吧!

Forwarding Other Ports

In addition to SSH's built-in support for X11, it can also be used to securely tunnel any TCP connection, by use of local forwarding or remote forwarding.

Local forwarding opens a port on the local machine, connections to which will be forwarded to the remote host and from there on to a given destination. Very often, the forwarding destination will be the same as the remote host, thus providing a secure shell and, e.g. a secure VNC connection, to the same machine. Local forwarding is accomplished by means of the switch and it's accompanying forwarding specification in the form of 

Thus:


$ ssh -L 1000:mail.google.com:25 192.168.0.100
will use SSH to login to and open a shell on 192.168.0.100, and will also create a tunnel from the local machine's TCP port 1000 to mail.google.com on port 25. Once established, connections to localhost:1000 will connect to the Gmail SMTP port. To Google, it will appear that any such connection (though not necessarily the data conveyed over the connection) originated from 192.168.0.100, and such data will be secure as between the local machine and 192.168.0.100, but not between 192.168.0.100, unless other measures are taken.


Similarly:


$ ssh -L 2000:192.168.0.100:6001 192.168.0.100
will allow connections to localhost:2000 which will be transparently sent to the remote host on port 6001. The preceding example is useful for VNC connections using the vncserver utility--part of the tightvnc package--which, though very useful, is explicit about its lack of security.


Remote forwarding allows the remote host to connect to an arbitrary host via the SSH tunnel and the local machine, providing a functional reversal of local forwarding, and is useful for situations where, e.g., the remote host has limited connectivity due to firewalling. It is enabled with the switch and a forwarding specification in the form of.

Thus:


$ ssh -R 3000:irc.freenode.net:6667 192.168.0.200
will bring up a shell on 192.168.0.200, and connections from 192.168.0.200 to itself on port 3000 (remotely speaking, localhost:3000) will be sent over the tunnel to the local machine and then on to irc.freenode.net on port 6667, thus, in this example, allowing the use of IRC programs on the remote host to be used, even if port 6667 would normally be blocked to it.


Both local and remote forwarding can be used to provide a secure "gateway," allowing other computers to take advantage of an SSH tunnel, without actually running SSH or the SSH daemon by providing a bind-address for the start of the tunnel as part of the forwarding specification, e.g. 

The can be any address on the machine at the start of the tunnel,  (or blank), which, respectively, allow connections via the given address, via the loopback interface, or via any interface. By default, forwarding is limited to connections from the machine at the "beginning" of the tunnel, i.e. the is set to. Local forwarding requires no additional configuration, however remote forwarding is limited by the remote server's SSH daemon configuration. See the option in  for more information.

Speed up SSH

You can make all sessions to the same host use a single connection, which will greatly speed up subsequent logins, by adding these lines under the proper host in :

ControlMaster auto ControlPath ~/.ssh/socket-%r@%h:%p
ControlMaster auto
ControlPath ~/.ssh/socket-%r@%h:%p

Changing the ciphers used by SSH to less cpu-demanding ones can improve speed. In this aspect, the best choices are arcfour and blowfish-cbc. Please do not do this unless you know what you are doing; arcfour has a number of known weaknesses. To use them, run SSH with the 模板:Ic flag, like this:


$ ssh -c arcfour,blowfish-cbc user@server-address
To use them permanently, add this line under the proper host in :



Ciphers arcfour,blowfish-cbc
Another option to improve speed is to enable compression with the flag. A permanent solution is to add this line under the proper host in :



Compression yes
Login time can be shorten by using the flag, which bypasses IPv6 lookup. This can be made permanent by adding this line under the proper host in :



AddressFamily inet
Another way of making these changes permanent is to create an alias in:


alias ssh='ssh -C4c arcfour,blowfish-cbc'
Troubleshooting

Make sure your DISPLAY string is resolveable on the remote end:

$ ssh -X user@server-address
server $ echo $DISPLAY
localhost:10.0
server $ telnet localhost 6010
localhost/6010: lookup failure: Temporary failure in name resolution   

can be fixed by adding localhost to.

用SSHFS挂载远程文件系统

安装sshfs


# pacman -S sshfs
将你想要允许挂载SSH文件夹的用户添加到fuse组里



# gpasswd -a USER fuse
加载fuse模块(比如说在/etc/rc.conf中)


And then然后,在登录后,你就可以试着挂用sshfs载远程文件夹了:


# mkdir ~/remote_folder
# sshfs USER@remote_server:/tmp ~/remote_folder
上面的命令将把远程服务器上的/tmp文件夹挂载到本地的~/remote_folder目录下。复制任何文件到这个目录将使文件通过SCP通过网络传输。 Same concerns direct file editing, creating or removing.


当我们完成在远程文件夹下的工作,我们可以这样来卸载它:


# fusermount -u ~/remote_folder
如果我们需要经常在这个文件夹下,让它通过/etc/fstab挂载是一个明智的选择。这个办法可以让它在启动的时候挂载或者通过手动挂载(如果是noauto选项的话),而不需要每次都去挂载它。下面是一个简单的样本:
sshfs#USER@remote_server:/tmp /full/path/to/directory fuse defaults,auto 0 0


链接和参考



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