SSH 的用处有很多，比如远程服务器管理，博客搬家，创造安全的上网环境等。当然，很多人不愿意去记复杂的命令，在终端中逐一输入。因此，本文主要推荐几款各主流平台上用来做 SSH Tunnel 的免费客户端。文中软件并没有很详细的使用说明，只作为一般性介绍，如有不明请搜索之，或参考文后的 “推荐阅读” 部分。请注意和谐使用，也不要浪费资源。注意，此处仅仅讨论的是用来做 SSH Tunnel，所以部分软件并不能实现诸如 Putty 等 SSH 客户端软件所提供的功能。
SSH via 维基百科
SSH为Secure Shell的缩写，由IETF的网络工作小组（Network Working Group）所制定；SSH为建立在应用层和传输层基础上的安全协议。传统的网络服务程序，如FTP、POP和Telnet其本质上都是不安全的；因为它们在网络上用明文传送数据、用户帐号和用户口令，很容易受到中间人 （man-in-the-middle）攻击方式的攻击。就是存在另一个人或者一台机器冒充真正的服务器接收用户传给服务器的数据，然后再冒充用户把数据 传给真正的服务器。而SSH是目前较可靠，专为远程登录会话和其他网络服务提供安全性的协议。利用SSH协议可以有效防止远程管理过程中的信息泄露问题。透过SSH可以对所有传输的数据进行加密，也能够防止DNS欺骗和IP欺骗。SSH之另一项优点为其传输的数据是经过压缩的，所以可以加快传输的速度。SSH有很多功能，它既可以代替Telnet，又可以为FTP、POP、甚至为PPP提供一个安全的“通道”
一、Mac
(1). iSSH(只能添加一个ssh a/c)
| 软件名称: | iSSH |
|---|---|
| 价格: | 免费软件 / 免费 |
| 系统平台: | Mac OS X |
| 运行环境 | 所有 |
| https://managedway.dl.sourceforge.net/project/issh/iSSH/3.1/iSSH_3.1.zip https://sourceforge.net/projects/issh/ |
Mac 上小巧免费的客户端，类似于 Windows 上的 MyEnTunnel。对于没有诸多要求，仅仅需要进行 SSH Tunnel 的用户来说值得使用。目前有网友对官网版本进行了修改，可以开机启动及启动时自动连接，并加入了中文界面。
(2). sidestep (只能添加一个ssh a/c)
https://github.com/chetan51/sidestep/releases/download/1.4.1/Sidestep.ziphttp://chetansurpur.com/projects/sidestep/
http://macappstore.org/sidestep/
(3). SSH proxy app:(郑重推荐.可添加多个ssh a/c）
http://briteming.blogspot.com/2018/02/macssh-proxy-app.html
二、Linux
(1). Gnome SSH Tunnel Manager
| 软件名称 | Gnome SSH Tunnel Manager |
|---|---|
| 授权 / 价格 | 开源软件 / 免费 |
| 系统平台 | Linux |
| 运行环境 | Gnome |
| 网址 | 官方网站 |
gSTM 是一款运行于 Gnome 上的用于 SSH Tunnel 的开源客户端，对于多账户管理比较方便。注：其配置文件是以 XML 格式保存。
具体使用可以参照 “Manage SSH Tunnels with Gnome SSH Tunnel Manager @ Ubuntu Geek”
具体使用可以参照 “Manage SSH Tunnels with Gnome SSH Tunnel Manager @ Ubuntu Geek”
(2). SSH Tunnel Manager
| 软件名称 | SSH Tunnel Manager |
|---|---|
| 授权 / 价格 | 开源软件（GPLv2） / 免费 |
| 系统平台 | Linux |
| 运行环境 | PyGtk |
| 网址 | 官方网站 |
一款使用 Python 开发的客户端。据作者所说，由于 Ubuntu 自带的客户端不能满足其要求，也作为学习 PyGtk
开发的实践，因此有了本软件。如果，你也是正在学习 PyGtk 或者对 Ubuntu 自带的客户端不满意，不妨试试，具体功能说明请参考官网。
另外有个带GUI界面的工具：ssh tunnel manager
修改：sudo vi /etc/ssh_config
（mac上的SSH Tunnel Manager
SSH Tunnel Manager lets you easily create network "tunnels" in situations where you cannot connect to some device but have a way to connect to as server nearby using SSH. It uses the ssh command bundled with the system.
Information
License
Free
Developer’s website
https://www.tynsoe.org/stm/https://dl.devmate.com/org.tynsoe.sshtunnelmanager/227.006/1478083232/SSHTunnelManager-227.006.zip
App requirements
- Intel 64
- Mac OS X 10.7 or later
from https://www.macupdate.com/app/mac/10128/ssh-tunnel-manager）
（Mac OSX上的ssh tunnel 代理设置备忘: ssh -i /path/to/key -D 1080 -C -N remoteuser@remote.host
最简单的是打开终端，然后直接用命令行：
ssh -i /path/to/key -D 1080 -C -N remoteuser@remote.host
-D 设置动态转发端口号；然后就可以设置应用通过代理访问了；
-C 启用压缩；
-N 不执行远程shell命令(ssh2支持)，登录后不会有提示行；
-i 优先使用秘钥key 而不是密码；
结合ssh key agent可以自动载入key和转发
sudo ssh-add -K /path/to/key
修改：sudo vi /etc/ssh_config
ForwardAgent yes
IdentityFile /path/to/key
from https://www.chedong.com/blog/archives/001403.html)
(3). Terminal
使用终端命令，应该是最符合 Linux 大部分用户习惯的方式了: ssh -qTfnN -D 7070 remotehost
以下为参数说明：
All the added options are for a ssh session that’s used for tunneling.
All the added options are for a ssh session that’s used for tunneling.
-q :- be very quite, we are acting only as a tunnel.
-T :- Do not allocate a pseudo tty, we are only acting a tunnel.
-f :- move the ssh process to background, as we don’t want to interact with this ssh session directly.
-N :- Do not execute remote command.
-n :- redirect standard input to /dev/null.
-T :- Do not allocate a pseudo tty, we are only acting a tunnel.
-f :- move the ssh process to background, as we don’t want to interact with this ssh session directly.
-N :- Do not execute remote command.
-n :- redirect standard input to /dev/null.
In addition on a slow line you can gain performance by enabling compression with the -C option.
三、Windows
(1). MyEnTunnel
| 软件名称 | MyEnTunnel |
|---|---|
| 授权 / 价格 | 免费软件 / 免费 |
| 系统平台 | Windows |
| 运行环境 | 所有 |
| 网址 | 官方网站 |
MyEnTunnel 对于使用 SSH Tunnel 的 Windows
用户来说，应该是众所周知了，小巧、快速、免费。但之前一直有速度问题，在下载大文件或者浏览视频网站时，速度一般。之前有很多网站提供了解决办法，目前
官网也指出了这个问题，并表示使用最新开发版的 plink.exe 可以解决这一问题。另外，最新 3.5.2 已经开始支持 Unicode 了。
(2). Bitvise Tunnelier
| 软件名称 | Bitvise Tunnelier |
|---|---|
| 授权 / 价格 | 个人免费 / 免费 |
| 系统平台 | Windows |
| 运行环境 | 所有 |
| 网址 | 官方网站 |
Bitvise Tunnelier 是近一段时间流行起来的 SSH Tunnel
客户端软件，由于功能强大，速度快并能保存多个配置文件而受到许多人的喜爱。对于 SSH 有诸多功能要求的用户是一个好选择。目前，软言软语在
Windows 上使用的是该款客户端，不仅仅可以 SSH Tunnel。
以此格式可以设置启动自动连接：”C:\Program Files\Bitvise Tunnelier\Tunnelier.exe” -profile=iusesoft.info.tlp -loginOnStartup，推荐创建一个快捷方式，并如此设置。
四、iPhone / iPod touch
1.
iSSH (App
Store)
iSSH 与 Mac 上的 iSSH 并不是一个公司的产品。而且此 iSSH 并不免费，售价为 9.99 美元。目前 iSSH 只能用来进行远程连接，并不能进行端口重定向。
2. MobileTerminal (Google Code)
需要 iPhone/iPod touch 已经 jailbreak 过，并安装了 OpenSSH。打开 MobileTerminal 输入：ssh -D 7070 username@host，然后输入密码即可。想要关闭，可以在终端输入 killall ssh，如果仍处于 SSH 登录状态，可以直接输入 logout。五、Android 【2010-11-29 新增】
目前在 Android 上 SSH Tunnel 的应用还不明朗，虽然已经有人将 TTP/HTTPS 重定向到 SSH Tunnel，但似乎还有一些问题。本人没有 Android 手机，因此无条件验证，有兴趣的用户可以参考以下内容：1. ConnectBot (Google Code)
ConnectBot 是 Android 平台上一款开源 SSH 客户端软件。2. SSH Tunneling On Android via Shantanu’s Technophilic Musings
3. SSH Tunnel for Android System【2011-07-27 新增】
一款国人基于 ConnectBot 开发而来的 SSH tunnel 工具。应用文章看这里。推荐阅读
--------------------------------------------------------------------
SYNOPSIS
ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface] [-b bind_address] [-c cipher_spec]
[-D [bind_address:]port] [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]
[-i identity_file] [-J destination] [-L address] [-l login_name] [-m mac_spec]
[-O ctl_cmd] [-o option] [-p port] [-Q query_option] [-R address] [-S ctl_path]
[-W host:port] [-w local_tun[:remote_tun]] destination [command]
DESCRIPTION
ssh (SSH client) is a program for logging into a remote machine and for executing commands
on a remote machine. It is intended to provide secure encrypted communications between two
untrusted hosts over an insecure network. X11 connections, arbitrary TCP ports and
UNIX-domain sockets can also be forwarded over the secure channel.
ssh connects and logs into the specified destination, which may be specified as either
[user@]hostname or a URI of the form ssh://[user@]hostname[:port]. The user must prove
his/her identity to the remote machine using one of several methods (see below).
If a command is specified, it is executed on the remote host instead of a login shell.
The options are as follows:
-4 Forces ssh to use IPv4 addresses only.
-6 Forces ssh to use IPv6 addresses only.
-A Enables forwarding of connections from an authentication agent such as ssh-agent(1).
This can also be specified on a per-host basis in a configuration file.
Agent forwarding should be enabled with caution. Users with the ability to bypass
file permissions on the remote host (for the agent's UNIX-domain socket) can access
the local agent through the forwarded connection. An attacker cannot obtain key ma-
terial from the agent, however they can perform operations on the keys that enable
them to authenticate using the identities loaded into the agent. A safer alterna-
tive may be to use a jump host (see -J).
-a Disables forwarding of the authentication agent connection.
-B bind_interface
Bind to the address of bind_interface before attempting to connect to the destina-
tion host. This is only useful on systems with more than one address.
-b bind_address
Use bind_address on the local machine as the source address of the connection. Only
useful on systems with more than one address.
-C Requests compression of all data (including stdin, stdout, stderr, and data for for-
warded X11, TCP and UNIX-domain connections). The compression algorithm is the same
used by gzip(1). Compression is desirable on modem lines and other slow connec-
tions, but will only slow down things on fast networks. The default value can be
set on a host-by-host basis in the configuration files; see the Compression option.
-c cipher_spec
Selects the cipher specification for encrypting the session. cipher_spec is a
comma-separated list of ciphers listed in order of preference. See the Ciphers key-
word in ssh_config(5) for more information.
-D [bind_address:]port
Specifies a local "dynamic" application-level port forwarding. This works by allo-
cating a socket to listen to port on the local side, optionally bound to the speci-
fied bind_address. Whenever a connection is made to this port, the connection is
forwarded over the secure channel, and the application protocol is then used to de-
termine where to connect to from the remote machine. Currently the SOCKS4 and
SOCKS5 protocols are supported, and ssh will act as a SOCKS server. Only root can
forward privileged ports. Dynamic port forwardings can also be specified in the
configuration file.
IPv6 addresses can be specified by enclosing the address in square brackets. Only
the superuser can forward privileged ports. By default, the local port is bound in
accordance with the GatewayPorts setting. However, an explicit bind_address may be
used to bind the connection to a specific address. The bind_address of "localhost"
indicates that the listening port be bound for local use only, while an empty ad-
dress or '*' indicates that the port should be available from all interfaces.
-E log_file
Append debug logs to log_file instead of standard error.
-e escape_char
Sets the escape character for sessions with a pty (default: '~'). The escape char-
acter is only recognized at the beginning of a line. The escape character followed
by a dot ('.') closes the connection; followed by control-Z suspends the connection;
and followed by itself sends the escape character once. Setting the character to
"none" disables any escapes and makes the session fully transparent.
-F configfile
Specifies an alternative per-user configuration file. If a configuration file is
given on the command line, the system-wide configuration file (/etc/ssh/ssh_config)
will be ignored. The default for the per-user configuration file is ~/.ssh/config.
-f Requests ssh to go to background just before command execution. This is useful if
ssh is going to ask for passwords or passphrases, but the user wants it in the back-
ground. This implies -n. The recommended way to start X11 programs at a remote
site is with something like ssh -f host xterm.
If the ExitOnForwardFailure configuration option is set to "yes", then a client
started with -f will wait for all remote port forwards to be successfully estab-
lished before placing itself in the background.
-G Causes ssh to print its configuration after evaluating Host and Match blocks and
exit.
-g Allows remote hosts to connect to local forwarded ports. If used on a multiplexed
connection, then this option must be specified on the master process.
-I pkcs11
Specify the PKCS#11 shared library ssh should use to communicate with a PKCS#11 to-
ken providing keys for user authentication.
-i identity_file
Selects a file from which the identity (private key) for public key authentication
is read. The default is ~/.ssh/id_dsa, ~/.ssh/id_ecdsa, ~/.ssh/id_ecdsa_sk,
~/.ssh/id_ed25519, ~/.ssh/id_ed25519_sk and ~/.ssh/id_rsa. Identity files may also
be specified on a per-host basis in the configuration file. It is possible to have
multiple -i options (and multiple identities specified in configuration files). If
no certificates have been explicitly specified by the CertificateFile directive, ssh
will also try to load certificate information from the filename obtained by append-
ing -cert.pub to identity filenames.
-J destination
Connect to the target host by first making a ssh connection to the jump host de-
scribed by destination and then establishing a TCP forwarding to the ultimate desti-
nation from there. Multiple jump hops may be specified separated by comma charac-
ters. This is a shortcut to specify a ProxyJump configuration directive. Note that
configuration directives supplied on the command-line generally apply to the desti-
nation host and not any specified jump hosts. Use ~/.ssh/config to specify configu-
ration for jump hosts.
-K Enables GSSAPI-based authentication and forwarding (delegation) of GSSAPI creden-
tials to the server.
-k Disables forwarding (delegation) of GSSAPI credentials to the server.
-L [bind_address:]port:host:hostport
-L [bind_address:]port:remote_socket
-L local_socket:host:hostport
-L local_socket:remote_socket
Specifies that connections to the given TCP port or Unix socket on the local
(client) host are to be forwarded to the given host and port, or Unix socket, on the
remote side. This works by allocating a socket to listen to either a TCP port on
the local side, optionally bound to the specified bind_address, or to a Unix socket.
Whenever a connection is made to the local port or socket, the connection is for-
warded over the secure channel, and a connection is made to either host port
hostport, or the Unix socket remote_socket, from the remote machine.
Port forwardings can also be specified in the configuration file. Only the supe-
ruser can forward privileged ports. IPv6 addresses can be specified by enclosing
the address in square brackets.
By default, the local port is bound in accordance with the GatewayPorts setting.
However, an explicit bind_address may be used to bind the connection to a specific
address. The bind_address of "localhost" indicates that the listening port be bound
for local use only, while an empty address or '*' indicates that the port should be
available from all interfaces.
-l login_name
Specifies the user to log in as on the remote machine. This also may be specified
on a per-host basis in the configuration file.
-M Places the ssh client into "master" mode for connection sharing. Multiple -M op-
tions places ssh into "master" mode but with confirmation required using
ssh-askpass(1) before each operation that changes the multiplexing state (e.g. open-
ing a new session). Refer to the description of ControlMaster in ssh_config(5) for
details.
-m mac_spec
A comma-separated list of MAC (message authentication code) algorithms, specified in
order of preference. See the MACs keyword for more information.
-N Do not execute a remote command. This is useful for just forwarding ports.
-n Redirects stdin from /dev/null (actually, prevents reading from stdin). This must
be used when ssh is run in the background. A common trick is to use this to run X11
programs on a remote machine. For example, ssh -n shadows.cs.hut.fi emacs & will
start an emacs on shadows.cs.hut.fi, and the X11 connection will be automatically
forwarded over an encrypted channel. The ssh program will be put in the background.
(This does not work if ssh needs to ask for a password or passphrase; see also the
-f option.)
-O ctl_cmd
Control an active connection multiplexing master process. When the -O option is
specified, the ctl_cmd argument is interpreted and passed to the master process.
Valid commands are: "check" (check that the master process is running), "forward"
(request forwardings without command execution), "cancel" (cancel forwardings),
"exit" (request the master to exit), and "stop" (request the master to stop accept-
ing further multiplexing requests).
-o option
Can be used to give options in the format used in the configuration file. This is
useful for specifying options for which there is no separate command-line flag. For
full details of the options listed below, and their possible values, see
ssh_config(5).
AddKeysToAgent
AddressFamily
BatchMode
BindAddress
CanonicalDomains
CanonicalizeFallbackLocal
CanonicalizeHostname
CanonicalizeMaxDots
CanonicalizePermittedCNAMEs
CASignatureAlgorithms
CertificateFile
ChallengeResponseAuthentication
CheckHostIP
Ciphers
ClearAllForwardings
Compression
ConnectionAttempts
ConnectTimeout
ControlMaster
ControlPath
ControlPersist
DynamicForward
EscapeChar
ExitOnForwardFailure
FingerprintHash
ForwardAgent
ForwardX11
ForwardX11Timeout
ForwardX11Trusted
GatewayPorts
GlobalKnownHostsFile
GSSAPIAuthentication
GSSAPIKeyExchange
GSSAPIClientIdentity
GSSAPIDelegateCredentials
GSSAPIKexAlgorithms
GSSAPIRenewalForcesRekey
GSSAPIServerIdentity
GSSAPITrustDns
HashKnownHosts
Host
HostbasedAuthentication
HostbasedKeyTypes
HostKeyAlgorithms
HostKeyAlias
Hostname
IdentitiesOnly
IdentityAgent
IdentityFile
IPQoS
KbdInteractiveAuthentication
KbdInteractiveDevices
KexAlgorithms
LocalCommand
LocalForward
LogLevel
MACs
Match
NoHostAuthenticationForLocalhost
NumberOfPasswordPrompts
PasswordAuthentication
PermitLocalCommand
PKCS11Provider
Port
PreferredAuthentications
ProxyCommand
ProxyJump
ProxyUseFdpass
PubkeyAcceptedKeyTypes
PubkeyAuthentication
RekeyLimit
RemoteCommand
RemoteForward
RequestTTY
SendEnv
ServerAliveInterval
ServerAliveCountMax
SetEnv
StreamLocalBindMask
StreamLocalBindUnlink
StrictHostKeyChecking
TCPKeepAlive
Tunnel
TunnelDevice
UpdateHostKeys
User
UserKnownHostsFile
VerifyHostKeyDNS
VisualHostKey
XAuthLocation
-p port
Port to connect to on the remote host. This can be specified on a per-host basis in
the configuration file.
-Q query_option
Queries ssh for the algorithms supported for the specified version 2. The available
features are: cipher (supported symmetric ciphers), cipher-auth (supported symmetric
ciphers that support authenticated encryption), help (supported query terms for use
with the -Q flag), mac (supported message integrity codes), kex (key exchange algo-
rithms), kex-gss (GSSAPI key exchange algorithms), key (key types), key-cert (cer-
tificate key types), key-plain (non-certificate key types), key-sig (all key types
and signature algorithms), protocol-version (supported SSH protocol versions), and
sig (supported signature algorithms). Alternatively, any keyword from ssh_config(5)
or sshd_config(5) that takes an algorithm list may be used as an alias for the cor-
responding query_option.
-q Quiet mode. Causes most warning and diagnostic messages to be suppressed.
-R [bind_address:]port:host:hostport
-R [bind_address:]port:local_socket
-R remote_socket:host:hostport
-R remote_socket:local_socket
-R [bind_address:]port
Specifies that connections to the given TCP port or Unix socket on the remote
(server) host are to be forwarded to the local side.
This works by allocating a socket to listen to either a TCP port or to a Unix socket
on the remote side. Whenever a connection is made to this port or Unix socket, the
connection is forwarded over the secure channel, and a connection is made from the
local machine to either an explicit destination specified by host port hostport, or
local_socket, or, if no explicit destination was specified, ssh will act as a SOCKS
4/5 proxy and forward connections to the destinations requested by the remote SOCKS
client.
Port forwardings can also be specified in the configuration file. Privileged ports
can be forwarded only when logging in as root on the remote machine. IPv6 addresses
can be specified by enclosing the address in square brackets.
By default, TCP listening sockets on the server will be bound to the loopback inter-
face only. This may be overridden by specifying a bind_address. An empty
bind_address, or the address '*', indicates that the remote socket should listen on
all interfaces. Specifying a remote bind_address will only succeed if the server's
GatewayPorts option is enabled (see sshd_config(5)).
If the port argument is '0', the listen port will be dynamically allocated on the
server and reported to the client at run time. When used together with -O forward
the allocated port will be printed to the standard output.
-S ctl_path
Specifies the location of a control socket for connection sharing, or the string
"none" to disable connection sharing. Refer to the description of ControlPath and
ControlMaster in ssh_config(5) for details.
-s May be used to request invocation of a subsystem on the remote system. Subsystems
facilitate the use of SSH as a secure transport for other applications (e.g.
sftp(1)). The subsystem is specified as the remote command.
-T Disable pseudo-terminal allocation.
-t Force pseudo-terminal allocation. This can be used to execute arbitrary screen-
based programs on a remote machine, which can be very useful, e.g. when implementing
menu services. Multiple -t options force tty allocation, even if ssh has no local
tty.
-V Display the version number and exit.
-v Verbose mode. Causes ssh to print debugging messages about its progress. This is
helpful in debugging connection, authentication, and configuration problems. Multi-
ple -v options increase the verbosity. The maximum is 3.
-W host:port
Requests that standard input and output on the client be forwarded to host on port
over the secure channel. Implies -N, -T, ExitOnForwardFailure and
ClearAllForwardings, though these can be overridden in the configuration file or us-
ing -o command line options.
-w local_tun[:remote_tun]
Requests tunnel device forwarding with the specified tun(4) devices between the
client (local_tun) and the server (remote_tun).
The devices may be specified by numerical ID or the keyword "any", which uses the
next available tunnel device. If remote_tun is not specified, it defaults to "any".
See also the Tunnel and TunnelDevice directives in ssh_config(5).
If the Tunnel directive is unset, it will be set to the default tunnel mode, which
is "point-to-point". If a different Tunnel forwarding mode it desired, then it
should be specified before -w.
-X Enables X11 forwarding. This can also be specified on a per-host basis in a config-
uration file.
X11 forwarding should be enabled with caution. Users with the ability to bypass
file permissions on the remote host (for the user's X authorization database) can
access the local X11 display through the forwarded connection. An attacker may then
be able to perform activities such as keystroke monitoring.
For this reason, X11 forwarding is subjected to X11 SECURITY extension restrictions
by default. Please refer to the ssh -Y option and the ForwardX11Trusted directive
in ssh_config(5) for more information.
(Debian-specific: X11 forwarding is not subjected to X11 SECURITY extension restric-
tions by default, because too many programs currently crash in this mode. Set the
ForwardX11Trusted option to "no" to restore the upstream behaviour. This may change
in future depending on client-side improvements.)
-x Disables X11 forwarding.
-Y Enables trusted X11 forwarding. Trusted X11 forwardings are not subjected to the
X11 SECURITY extension controls.
(Debian-specific: In the default configuration, this option is equivalent to -X,
since ForwardX11Trusted defaults to "yes" as described above. Set the
ForwardX11Trusted option to "no" to restore the upstream behaviour. This may change
in future depending on client-side improvements.)
-y Send log information using the syslog(3) system module. By default this information
is sent to stderr.
ssh may additionally obtain configuration data from a per-user configuration file and a sys-
tem-wide configuration file. The file format and configuration options are described in
ssh_config(5).
AUTHENTICATION
The OpenSSH SSH client supports SSH protocol 2.
The methods available for authentication are: GSSAPI-based authentication, host-based au-
thentication, public key authentication, challenge-response authentication, and password au-
thentication. Authentication methods are tried in the order specified above, though
PreferredAuthentications can be used to change the default order.
Host-based authentication works as follows: If the machine the user logs in from is listed
in /etc/hosts.equiv or /etc/ssh/shosts.equiv on the remote machine, and the user names are
the same on both sides, or if the files ~/.rhosts or ~/.shosts exist in the user's home di-
rectory on the remote machine and contain a line containing the name of the client machine
and the name of the user on that machine, the user is considered for login. Additionally,
the server must be able to verify the client's host key (see the description of
/etc/ssh/ssh_known_hosts and ~/.ssh/known_hosts, below) for login to be permitted. This au-
thentication method closes security holes due to IP spoofing, DNS spoofing, and routing
spoofing. [Note to the administrator: /etc/hosts.equiv, ~/.rhosts, and the rlogin/rsh pro-
tocol in general, are inherently insecure and should be disabled if security is desired.]
Public key authentication works as follows: The scheme is based on public-key cryptography,
using cryptosystems where encryption and decryption are done using separate keys, and it is
unfeasible to derive the decryption key from the encryption key. The idea is that each user
creates a public/private key pair for authentication purposes. The server knows the public
key, and only the user knows the private key. ssh implements public key authentication pro-
tocol automatically, using one of the DSA, ECDSA, Ed25519 or RSA algorithms. The HISTORY
section of ssl(8) (on non-OpenBSD systems, see
http://www.openbsd.org/cgi-bin/man.cgi?query=ssl&sektion=8#HISTORY) contains a brief discus-
sion of the DSA and RSA algorithms.
The file ~/.ssh/authorized_keys lists the public keys that are permitted for logging in.
When the user logs in, the ssh program tells the server which key pair it would like to use
for authentication. The client proves that it has access to the private key and the server
checks that the corresponding public key is authorized to accept the account.
The server may inform the client of errors that prevented public key authentication from
succeeding after authentication completes using a different method. These may be viewed by
increasing the LogLevel to DEBUG or higher (e.g. by using the -v flag).
The user creates his/her key pair by running ssh-keygen(1). This stores the private key in
~/.ssh/id_dsa (DSA), ~/.ssh/id_ecdsa (ECDSA), ~/.ssh/id_ecdsa_sk (authenticator-hosted
ECDSA), ~/.ssh/id_ed25519 (Ed25519), ~/.ssh/id_ed25519_sk (authenticator-hosted Ed25519), or
~/.ssh/id_rsa (RSA) and stores the public key in ~/.ssh/id_dsa.pub (DSA),
~/.ssh/id_ecdsa.pub (ECDSA), ~/.ssh/id_ecdsa_sk.pub (authenticator-hosted ECDSA),
~/.ssh/id_ed25519.pub (Ed25519), ~/.ssh/id_ed25519_sk.pub (authenticator-hosted Ed25519), or
~/.ssh/id_rsa.pub (RSA) in the user's home directory. The user should then copy the public
key to ~/.ssh/authorized_keys in his/her home directory on the remote machine. The
authorized_keys file corresponds to the conventional ~/.rhosts file, and has one key per
line, though the lines can be very long. After this, the user can log in without giving the
password.
A variation on public key authentication is available in the form of certificate authentica-
tion: instead of a set of public/private keys, signed certificates are used. This has the
advantage that a single trusted certification authority can be used in place of many pub-
lic/private keys. See the CERTIFICATES section of ssh-keygen(1) for more information.
The most convenient way to use public key or certificate authentication may be with an au-
thentication agent. See ssh-agent(1) and (optionally) the AddKeysToAgent directive in
ssh_config(5) for more information.
Challenge-response authentication works as follows: The server sends an arbitrary
"challenge" text, and prompts for a response. Examples of challenge-response authentication
include BSD Authentication (see login.conf(5)) and PAM (some non-OpenBSD systems).
Finally, if other authentication methods fail, ssh prompts the user for a password. The
password is sent to the remote host for checking; however, since all communications are en-
crypted, the password cannot be seen by someone listening on the network.
ssh automatically maintains and checks a database containing identification for all hosts it
has ever been used with. Host keys are stored in ~/.ssh/known_hosts in the user's home di-
rectory. Additionally, the file /etc/ssh/ssh_known_hosts is automatically checked for known
hosts. Any new hosts are automatically added to the user's file. If a host's identifica-
tion ever changes, ssh warns about this and disables password authentication to prevent
server spoofing or man-in-the-middle attacks, which could otherwise be used to circumvent
the encryption. The StrictHostKeyChecking option can be used to control logins to machines
whose host key is not known or has changed.
When the user's identity has been accepted by the server, the server either executes the
given command in a non-interactive session or, if no command has been specified, logs into
the machine and gives the user a normal shell as an interactive session. All communication
with the remote command or shell will be automatically encrypted.
If an interactive session is requested ssh by default will only request a pseudo-terminal
(pty) for interactive sessions when the client has one. The flags -T and -t can be used to
override this behaviour.
If a pseudo-terminal has been allocated the user may use the escape characters noted below.
If no pseudo-terminal has been allocated, the session is transparent and can be used to re-
liably transfer binary data. On most systems, setting the escape character to "none" will
also make the session transparent even if a tty is used.
The session terminates when the command or shell on the remote machine exits and all X11 and
TCP connections have been closed.
ESCAPE CHARACTERS
When a pseudo-terminal has been requested, ssh supports a number of functions through the
use of an escape character.
A single tilde character can be sent as ~~ or by following the tilde by a character other
than those described below. The escape character must always follow a newline to be inter-
preted as special. The escape character can be changed in configuration files using the
EscapeChar configuration directive or on the command line by the -e option.
The supported escapes (assuming the default '~') are:
~. Disconnect.
~^Z Background ssh.
~# List forwarded connections.
~& Background ssh at logout when waiting for forwarded connection / X11 sessions to
terminate.
~? Display a list of escape characters.
~B Send a BREAK to the remote system (only useful if the peer supports it).
~C Open command line. Currently this allows the addition of port forwardings using the
-L, -R and -D options (see above). It also allows the cancellation of existing
port-forwardings with -KL[bind_address:]port for local, -KR[bind_address:]port for
remote and -KD[bind_address:]port for dynamic port-forwardings. !command allows the
user to execute a local command if the PermitLocalCommand option is enabled in
ssh_config(5). Basic help is available, using the -h option.
~R Request rekeying of the connection (only useful if the peer supports it).
~V Decrease the verbosity (LogLevel) when errors are being written to stderr.
~v Increase the verbosity (LogLevel) when errors are being written to stderr.
TCP FORWARDING
Forwarding of arbitrary TCP connections over a secure channel can be specified either on the
command line or in a configuration file. One possible application of TCP forwarding is a
secure connection to a mail server; another is going through firewalls.
In the example below, we look at encrypting communication for an IRC client, even though the
IRC server it connects to does not directly support encrypted communication. This works as
follows: the user connects to the remote host using ssh, specifying the ports to be used to
forward the connection. After that it is possible to start the program locally, and ssh
will encrypt and forward the connection to the remote server.
The following example tunnels an IRC session from the client to an IRC server at
"server.example.com", joining channel "#users", nickname "pinky", using the standard IRC
port, 6667:
$ ssh -f -L 6667:localhost:6667 server.example.com sleep 10
$ irc -c '#users' pinky IRC/127.0.0.1
The -f option backgrounds ssh and the remote command "sleep 10" is specified to allow an
amount of time (10 seconds, in the example) to start the program which is going to use the
tunnel. If no connections are made within the time specified, ssh will exit.
X11 FORWARDING
If the ForwardX11 variable is set to "yes" (or see the description of the -X, -x, and -Y op-
tions above) and the user is using X11 (the DISPLAY environment variable is set), the con-
nection to the X11 display is automatically forwarded to the remote side in such a way that
any X11 programs started from the shell (or command) will go through the encrypted channel,
and the connection to the real X server will be made from the local machine. The user
should not manually set DISPLAY. Forwarding of X11 connections can be configured on the
command line or in configuration files.
The DISPLAY value set by ssh will point to the server machine, but with a display number
greater than zero. This is normal, and happens because ssh creates a "proxy" X server on
the server machine for forwarding the connections over the encrypted channel.
ssh will also automatically set up Xauthority data on the server machine. For this purpose,
it will generate a random authorization cookie, store it in Xauthority on the server, and
verify that any forwarded connections carry this cookie and replace it by the real cookie
when the connection is opened. The real authentication cookie is never sent to the server
machine (and no cookies are sent in the plain).
If the ForwardAgent variable is set to "yes" (or see the description of the -A and -a op-
tions above) and the user is using an authentication agent, the connection to the agent is
automatically forwarded to the remote side.
VERIFYING HOST KEYS
When connecting to a server for the first time, a fingerprint of the server's public key is
presented to the user (unless the option StrictHostKeyChecking has been disabled). Finger-
prints can be determined using ssh-keygen(1):
$ ssh-keygen -l -f /etc/ssh/ssh_host_rsa_key
If the fingerprint is already known, it can be matched and the key can be accepted or re-
jected. If only legacy (MD5) fingerprints for the server are available, the ssh-keygen(1)
-E option may be used to downgrade the fingerprint algorithm to match.
Because of the difficulty of comparing host keys just by looking at fingerprint strings,
there is also support to compare host keys visually, using random art. By setting the
VisualHostKey option to "yes", a small ASCII graphic gets displayed on every login to a
server, no matter if the session itself is interactive or not. By learning the pattern a
known server produces, a user can easily find out that the host key has changed when a com-
pletely different pattern is displayed. Because these patterns are not unambiguous however,
a pattern that looks similar to the pattern remembered only gives a good probability that
the host key is the same, not guaranteed proof.
To get a listing of the fingerprints along with their random art for all known hosts, the
following command line can be used:
$ ssh-keygen -lv -f ~/.ssh/known_hosts
If the fingerprint is unknown, an alternative method of verification is available: SSH fin-
gerprints verified by DNS. An additional resource record (RR), SSHFP, is added to a zone-
file and the connecting client is able to match the fingerprint with that of the key pre-
sented.
In this example, we are connecting a client to a server, "host.example.com". The SSHFP re-
source records should first be added to the zonefile for host.example.com:
$ ssh-keygen -r host.example.com.
The output lines will have to be added to the zonefile. To check that the zone is answering
fingerprint queries:
$ dig -t SSHFP host.example.com
Finally the client connects:
$ ssh -o "VerifyHostKeyDNS ask" host.example.com
[...]
Matching host key fingerprint found in DNS.
Are you sure you want to continue connecting (yes/no)?
See the VerifyHostKeyDNS option in ssh_config(5) for more information.
SSH-BASED VIRTUAL PRIVATE NETWORKS
ssh contains support for Virtual Private Network (VPN) tunnelling using the tun(4) network
pseudo-device, allowing two networks to be joined securely. The sshd_config(5) configura-
tion option PermitTunnel controls whether the server supports this, and at what level (layer
2 or 3 traffic).
The following example would connect client network 10.0.50.0/24 with remote network
10.0.99.0/24 using a point-to-point connection from 10.1.1.1 to 10.1.1.2, provided that the
SSH server running on the gateway to the remote network, at 192.168.1.15, allows it.
On the client:
# ssh -f -w 0:1 192.168.1.15 true
# ifconfig tun0 10.1.1.1 10.1.1.2 netmask 255.255.255.252
# route add 10.0.99.0/24 10.1.1.2
On the server:
# ifconfig tun1 10.1.1.2 10.1.1.1 netmask 255.255.255.252
# route add 10.0.50.0/24 10.1.1.1
Client access may be more finely tuned via the /root/.ssh/authorized_keys file (see below)
and the PermitRootLogin server option. The following entry would permit connections on
tun(4) device 1 from user "jane" and on tun device 2 from user "john", if PermitRootLogin is
set to "forced-commands-only":
tunnel="1",command="sh /etc/netstart tun1" ssh-rsa ... jane
tunnel="2",command="sh /etc/netstart tun2" ssh-rsa ... john
Since an SSH-based setup entails a fair amount of overhead, it may be more suited to tempo-
rary setups, such as for wireless VPNs. More permanent VPNs are better provided by tools
such as ipsecctl(8) and isakmpd(8).
ENVIRONMENT
ssh will normally set the following environment variables:
DISPLAY The DISPLAY variable indicates the location of the X11 server. It is
automatically set by ssh to point to a value of the form "hostname:n",
where "hostname" indicates the host where the shell runs, and 'n' is
an integer >= 1. ssh uses this special value to forward X11 connec-
tions over the secure channel. The user should normally not set
DISPLAY explicitly, as that will render the X11 connection insecure
(and will require the user to manually copy any required authorization
cookies).
HOME Set to the path of the user's home directory.
LOGNAME Synonym for USER; set for compatibility with systems that use this
variable.
MAIL Set to the path of the user's mailbox.
PATH Set to the default PATH, as specified when compiling ssh.
SSH_ASKPASS If ssh needs a passphrase, it will read the passphrase from the cur-
rent terminal if it was run from a terminal. If ssh does not have a
terminal associated with it but DISPLAY and SSH_ASKPASS are set, it
will execute the program specified by SSH_ASKPASS and open an X11 win-
dow to read the passphrase. This is particularly useful when calling
ssh from a .xsession or related script. (Note that on some machines
it may be necessary to redirect the input from /dev/null to make this
work.)
SSH_AUTH_SOCK Identifies the path of a UNIX-domain socket used to communicate with
the agent.
SSH_CONNECTION Identifies the client and server ends of the connection. The variable
contains four space-separated values: client IP address, client port
number, server IP address, and server port number.
SSH_ORIGINAL_COMMAND This variable contains the original command line if a forced command
is executed. It can be used to extract the original arguments.
SSH_TTY This is set to the name of the tty (path to the device) associated
with the current shell or command. If the current session has no tty,
this variable is not set.
SSH_TUNNEL Optionally set by sshd(8) to contain the interface names assigned if
tunnel forwarding was requested by the client.
SSH_USER_AUTH Optionally set by sshd(8), this variable may contain a pathname to a
file that lists the authentication methods successfully used when the
session was established, including any public keys that were used.
TZ This variable is set to indicate the present time zone if it was set
when the daemon was started (i.e. the daemon passes the value on to
new connections).
USER Set to the name of the user logging in.
Additionally, ssh reads ~/.ssh/environment, and adds lines of the format "VARNAME=value" to
the environment if the file exists and users are allowed to change their environment. For
more information, see the PermitUserEnvironment option in sshd_config(5).
FILES
~/.rhosts
This file is used for host-based authentication (see above). On some machines this
file may need to be world-readable if the user's home directory is on an NFS parti-
tion, because sshd(8) reads it as root. Additionally, this file must be owned by
the user, and must not have write permissions for anyone else. The recommended per-
mission for most machines is read/write for the user, and not accessible by others.
~/.shosts
This file is used in exactly the same way as .rhosts, but allows host-based authen-
tication without permitting login with rlogin/rsh.
~/.ssh/
This directory is the default location for all user-specific configuration and au-
thentication information. There is no general requirement to keep the entire con-
tents of this directory secret, but the recommended permissions are read/write/exe-
cute for the user, and not accessible by others.
~/.ssh/authorized_keys
Lists the public keys (DSA, ECDSA, Ed25519, RSA) that can be used for logging in as
this user. The format of this file is described in the sshd(8) manual page. This
file is not highly sensitive, but the recommended permissions are read/write for the
user, and not accessible by others.
~/.ssh/config
This is the per-user configuration file. The file format and configuration options
are described in ssh_config(5). Because of the potential for abuse, this file must
have strict permissions: read/write for the user, and not writable by others. It
may be group-writable provided that the group in question contains only the user.
~/.ssh/environment
Contains additional definitions for environment variables; see ENVIRONMENT, above.
~/.ssh/id_dsa
~/.ssh/id_ecdsa
~/.ssh/id_ecdsa_sk
~/.ssh/id_ed25519
~/.ssh/id_ed25519_sk
~/.ssh/id_rsa
Contains the private key for authentication. These files contain sensitive data and
should be readable by the user but not accessible by others (read/write/execute).
ssh will simply ignore a private key file if it is accessible by others. It is pos-
sible to specify a passphrase when generating the key which will be used to encrypt
the sensitive part of this file using AES-128.
~/.ssh/id_dsa.pub
~/.ssh/id_ecdsa.pub
~/.ssh/id_ecdsa_sk.pub
~/.ssh/id_ed25519.pub
~/.ssh/id_ed25519_sk.pub
~/.ssh/id_rsa.pub
Contains the public key for authentication. These files are not sensitive and can
(but need not) be readable by anyone.
~/.ssh/known_hosts
Contains a list of host keys for all hosts the user has logged into that are not al-
ready in the systemwide list of known host keys. See sshd(8) for further details of
the format of this file.
~/.ssh/rc
Commands in this file are executed by ssh when the user logs in, just before the
user's shell (or command) is started. See the sshd(8) manual page for more informa-
tion.
/etc/hosts.equiv
This file is for host-based authentication (see above). It should only be writable
by root.
/etc/ssh/shosts.equiv
This file is used in exactly the same way as hosts.equiv, but allows host-based au-
thentication without permitting login with rlogin/rsh.
/etc/ssh/ssh_config
Systemwide configuration file. The file format and configuration options are de-
scribed in ssh_config(5).
/etc/ssh/ssh_host_key
/etc/ssh/ssh_host_dsa_key
/etc/ssh/ssh_host_ecdsa_key
/etc/ssh/ssh_host_ed25519_key
/etc/ssh/ssh_host_rsa_key
These files contain the private parts of the host keys and are used for host-based
authentication.
/etc/ssh/ssh_known_hosts
Systemwide list of known host keys. This file should be prepared by the system ad-
ministrator to contain the public host keys of all machines in the organization. It
should be world-readable. See sshd(8) for further details of the format of this
file.
/etc/ssh/sshrc
Commands in this file are executed by ssh when the user logs in, just before the
user's shell (or command) is started. See the sshd(8) manual page for more informa-
tion.
EXIT STATUS
ssh exits with the exit status of the remote command or with 255 if an error occurred.
SEE ALSO
scp(1), sftp(1), ssh-add(1), ssh-agent(1), ssh-argv0(1), ssh-keygen(1), ssh-keyscan(1),
tun(4), ssh_config(5), ssh-keysign(8), sshd(8)from https://www.chedong.com/phpMan.php/man/ssh/1
(https://www.chedong.com/phpMan.php/man/ssh-copy-id/1)
----------------------------------------------------------------------
http://web.archive.org/web/20071011015037/http://blog.dreamhosters.com/kbase/index.cgi?area=138
http://web.archive.org/web/20071216043815/http://wiki.dreamhost.com/index.php/Secure_E-mail#Tunneling_over_SSH_in_Windows
http://web.archive.org/web/20071203023946/http://wiki.dreamhost.com/index.php/Mysql#Connect_to_Your_MySQL_Database_from_Third-Party_Programs_via_a_Secure_SSH_Tunnel
http://web.archive.org/web/20080105154613/http://blog.dreamhosters.com/2006/05/26/more-tips-for-secure-communication/
-------------------------------------------------
SSH Tunnel之fuck GFW整体解决方案
在不能使用代理服务器或者tor绕开防火长城的场合（比如单位里面不可以使用非企业代理，比如日后tor被土共封锁），如果ssh 22端口没有被封锁，那就可以利用OpenSSH强大的tunnel功能来
实现高速安全的访问Internet任意开放网站的任意开放端口 。在这里简称挖地道
1准备条件：
1.1 某国外主机shell，这个需要你自己去找，买一个或找找一个免费的，需要上面的开启sshd
1.2 Firefox浏览器配合foxyproxy扩展，虽然用IE也方便，但是当大多数网站不需要挖地道访问只有个别网站需要挖地道访问自己又是懒人懒得每次访问blocked网站去切换浏览器的代理设置的情况下，用foxyproxy这个基于模版自动匹配代理的扩展还是很方便的。
1.3 国外代理服务器，任意一个高速匿名免费代理服务器
2原理：
2.1首先man ssh，注意ssh的manpage里面这也一个选项：
-L port:host:hostport
Specifies that the given port on the local (client) host is to be
forwarded to the given host and port on the remote side. This
works by allocating a socket to listen to port on the local side,
and whenever a connection is made to this port, the connection is
forwarded over the secure channel, and a connection is made to
host port hostport from the remote machine. Port forwardings can
also be specified in the configuration file. Only root can for-
ward privileged ports. IPv6 addresses can be specified with an
alternative syntax: port/host/hostport
2.2基本格式
ssh -l USER -L local_port:any_host_blocked_by_gfw:the_blocked_hosts_port ssh host_which_out_of_gfw
这样任何被屏蔽的主机(any_host_blocked_by_gfw)的任何端口(the_blocked_hosts_port)，就可以在本机127.0.0.1的localport访问了
2.3解释，这里有好几个host不要搞错。
ssh -l USER是你用来登录目标ssh主机的用户名，ssh就加上一个-l选项
local_port:本机的某端口，最好大一些，保证没有被其他程序占用的，以后被屏蔽主机的某端口就被映射在本机的此端口
any_host_blocked_by_gfw:任何一个被gfw干了的主机，比如zh.wikipedia.org
the_blocked_hosts_port:前面提到的被干了的这个主机的某个端口，比如25 23 80
host_which_out_of_gfw：任何一台不在土共的GFW范围内的ssh host
2.4例子：
ssh -l fuckGFW 8088:zh.wikipedia.org:80 fuckgfw.free.com
我用fuckGFW帐号登录fuckgfw.free.com主机，并且把维基百科中文的80端口映射到本机的8088端口，这样下次用http://localhost:8088来访问维基百科
3应用：
每次去挖这样一个坑麻烦了点，这时候就要动动脑筋想想别的办法了。普通的代理服务访问国外主机虽然会被土共的gfw盾，但是，如果把普通国外代理服务器加上一个ssh的套套，那土共的GFW就煞笔了，而且即使土共把这个代理服务器本身干了也没用，因为我们的国外ssh
host和国外的代理服务器都是在GFW之外的，那就是终极解决方案：
用ssh tunnel给国外代理服务器加套
例子：
ssh -l fuckGFW 3128:proxy.anywhere.com:8080 fuckgfw.free.com
按照提示输入fuckGFW帐号在fuckfw.free.com主机的密码，然后保持这个ssh连接不要关掉，
这样就给国外的代理服务器proxy.anywhere.com加了套，然后在本地的浏览器设置代理为localhost:3128，那么只要你到fuckgfw.free.com的连接是22端口的ssh加密连接，土共就对你的内容无可奈何。
至于fuckgfw.free.com和proxy.anywhere.com之间是不是加密的会不会监听，目前看来似乎是不加密的（否则我在防火墙内我的本机开一个ssh再加上一个squid就可以访问任意国外主机了)，所有这样做还是有风 险，千万不要用这样的方案访问你的paypal帐号gmail等等。但是用来绕开防火墙，正常使用google是足够了，访问blogspot wikipedia等等也没有问题。
此方案的突出几个优点：
a:不需要在ssh主机上面安装软件，这样需要相对较少的ssh shell权限，很多免费的国外ssh主机就可以达到这个要求。
b:不需要在ssh主机上面开允许连入的端口，这样也可以减少对ssh 主机的需求，很多ssh主机只允许22端口连入时，我们这个方法也可以奏效，以上面的例子，3128端口是开设在你自己使用的client 机器的，8080端口是开设在代理服务器proxy.anywhere.com的，ssh主机上面并没有开设额外的端口，还是只有一个22端口。当然，ssh主机应该可以访问intenet的任何端口，这个应该不是问题的吧。
c：安全。开设在client的端口默认是只允许client本机访问的，同一局域网无法访问，除非你调整ssh client的设置。而且前面提到的，主机上面除了原先的22端口也不开设任何额外的端口，非常的安全。也避免了自己秘密安装的防火墙被其他人透露后带来流量激增的问题。
d：专门针对GFW的关键字过滤，这个方法同其他的绕开GFW主机方案比如在你购买的国外主机安装Phpproxy等等最大的不同和优点在于此。防火墙最难对付的地方并不是直接block主机地址，而是当访问国外主机返回的字符中有所谓敏感字词的时候给你来个链接重置，非常的讨厌。用普通的代理服务器（无论是国外的还是你自己安装的还是pkblogs.com等等这种类型的） 可以轻松的绕开GFW对block主机地址的屏蔽，但是当有敏感字词的时候还是难逃法眼。而这个方法，由于从你的client到ssh host之间是ssh密文传播的，GFW无能为力。
4.To Do
通常网上容易找到的代理服务器都是只支持http的，支持https的还没有找到，所以访问https的内容比如gmail还是没有好的解决方法，目前只能设置一下foxyproxy直接访问https的内容(或者用tor)，还有一个办法就是再挖一个通道，把gmail的pop服务器的端口和smtp直接映射在本地的某端口，宁可暂时放弃一下gmail
web的丰富feature，也要不受限制的访问google的服务。注意，在ssh到一台主机的时候，可以同时挖n条隧道的，也就是可以在ssh命令后面加上n个-L
参数
5.补充
使用windows操作系统的也可以用此方法，putty对ssh的tunnel有完美的支持。
抓图一张作为例子，第一行是我自己用的http代理，马赛克一下，hoho，第二行和第三行把gmail的pop.google.com和smtp.google.com的端口加了ssh的套套分别映射到了本机的995和587端口,下面正在填写的那个是一个例子，把国外代理服务器的anyproxy.abroad.com的8080端口加ssh套套映射到本地的5088端口，供浏览器作为代理服务器
localhost:5088使用。
from http://yesure.blogspot.com/2006/11/ssh-tunnelfuck-gfw.html
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相关帖子：
https://briteming.blogspot.com/2012/11/ssh-tunnel-proxy-how-to-set-it-up-with.html
