Forwards remote services over proxy to local ports; local applications do not need to be SOCKS-aware.
How To Use
You can specify proxy method in an environment variable or in a command line option.
usage: connect [-dnhst45N] [-R resolve] [-p local-port] [-w sec] [-H [user@]proxy-server[:port]] [-S [user@]socks-server[:port]] [-T proxy-server[:port]] [-c telnet proxy command] host port
"host" and "port" is for the target hostname and port-number to connect to.
The -H option specifys a hostname and port number of the http proxy server to relay. If port is omitted, 80 is used. You can specify this value in the environment variable HTTP_PROXY and pass the -h option to use it.
The -S option specifys the hostname and port number of the SOCKS server to relay. Like -H, port number can be omitted and the default is 1080. You can also specify this value pair in the environment variable SOCKS5_SERVER and give the -s option to use it.
The '-4' and the '-5' options are for specifying SOCKS relaying and indicates protocol version to use. It is valid only when used with '-s' or '-S'. Default is '-5' (protocol version 5)
The '-R' option is for specifying method to resolve the hostname. Three keywords ("local", "remote", "both") or dot-notation IP address are acceptable. The keyword "both" means, "Try local first, then remote". If a dot-notation IP address is specified, use this host as nameserver. The default is "remote" for SOCKS5 or "local" for others. On SOCKS4 protocol, remote resolving method ("remote" and "both") requires protocol 4a supported server.
The '-p' option will forward a local TCP port instead of using the standard input and output.
The '-P' option is same to '-p' except keep remote session. The program repeats waiting the port with holding remote session without disconnecting. To disconnect the remote session, send EOF to stdin or kill the program.
The '-w' option specifys timeout seconds for making connection with TARGET host.
The '-N' option selects for no authentication when it is available. Otherwise, connect.c defaults to use authentication.
The '-d' option is used for debug. If you fail to connect, use this and check request to and response from server.
You can omit the "port" argument when program name is special format containing port number itself. For example, $ ln -s connect connect-25 means this connect-25 command is spcifying port number 25 already so you need not 2nd argument (and ignored if specified).
To use proxy, this example is for SOCKS5 connection to connect to 'host' at port 25 via SOCKS5 server on 'firewall' host. $ connect -S firewall host 25 or $ SOCKS5_SERVER=firewall; export SOCKS5_SERVER $ connect -s host 25
For a HTTP-PROXY connection: $ connect -H proxy-server:8080 host 25 or $ HTTP_PROXY=proxy-server:8080; export HTTP_PROXY $ connect -h host 25 To forward a local port, for example to use ssh: $ connect -p 5550 -H proxy-server:8080 host 22 ($ ssh -l user -p 5550 localhost )
TIPS
Connect.c doesn't have any configuration to specify the SOCKS server. If you are a mobile user, this limitation might bother you. However, You can compile connect.c and link with other standard SOCKS library like the NEC SOCKS5 library or Dante. This means connect.c is socksified and uses a configration file like to other SOCKSified network commands and you can switch configuration file any time (ex. when ppp startup) that brings you switching of SOCKS server for connect.c in same way with other commands. For this case, you can write ~/.ssh/config like this:
ProxyCommand connect -n %h %p
SOCKS5 authentication
Only USER/PASS authentication is supported.
Proxy authentication
Only BASIC scheme is supported.
Authentication informations
User name for authentication is specifed by an environment variable or system login name. And password is specified from environment variable or external program (specified in $SSH_ASKPASS) or tty.
Following environment variable is used for specifying user name. SOCKS: $SOCKS5_USER, $LOGNAME, $USER HTTP Proxy: $HTTP_PROXY_USER, $LOGNAME, $USER
ssh-askpass support
You can use ssh-askpass (came from OpenSSH or else) to specify password on graphical environment (X-Window or MS Windows). To use this, set program name to environment variable SSH_ASKPASS. On UNIX, X-Window must be required, so $DISPLAY environment variable is also needed. On Win32 environment, $DISPLAY is not mentioned.
Related Informations
SOCKS5 -- RFC 1928, RFC 1929, RFC 1961 NEC SOCKS Reference Implementation is available from: http://www.socks.nec.com DeleGate version 5 or earlier can be SOCKS4 server, and version 6 can be SOCKS5 and SOCKS4 server. and version 7.7.0 or later can be SOCKS5 and SOCKS4a server. http://www.delegate.org/delegate/
HTTP-Proxy -- Many http proxy servers supports this, but https should be allowed as configuration on your host. For example on DeleGate, you should add "https" to the "REMITTABLE" parameter to allow HTTP-Proxy like this: delegated -Pxxxx ...... REMITTABLE="+,https" ...
Hypertext Transfer Protocol -- HTTP/1.1 -- RFC 2616 HTTP Authentication: Basic and Digest Access Authentication -- RFC 2617 For proxy authentication, refer these documents.
Getting Source (stale)
Recent version of 'connect.c' is available from http://www.taiyo.co.jp/~gotoh/ssh/connect.c (Dead link now. -CEM)
Related tool, ssh-askpass.exe (alternative ssh-askpass on UNIX) is available: http://www.taiyo.co.jp/~gotoh/ssh/ssh-askpass.exe.gz
See more detail: http://www.taiyo.co.jp/~gotoh/ssh/connect.html
