Proxy

References

• For SSH, check excellent page on Yobi wiki on how to bypass corporate proxy using SSH.
• Good FAQ on proxy.
  • Details on HTTP proxy
• HTTHost+HTTPort is a free software to create a HTTP tunnel through a proxy to connect to any remote host/port (using SSL/CONNECT). It also provides software to run a remote host to which HTTHost can tunnel through.
• List of free HTTP proxies:
  • http://www.atomintersoft.com/products/alive-proxy/proxy-list/
  • http://djsyndrome.homestead.com/proxies1.html
  • http://proxys4all.cgi.net/

Bypassing proxy - SSH

Check Yobi wiki page above to bypass proxy using SSH.

Example of commands to connect to remote IMAP server, tunneling through a SSH proxy:

ssh -f -N -R143:ton.imap.server:143 un.serveur.ssh.quelconque

Bypassing proxy - HTTP

The principle is to install a software on local machine that will map local port to a remote host port, and tunneling all traffic through an intermediate proxy. They are basically 2 methods:

• Without a remote host server. It requires the proxy to support SSL/CONNECT commands (usually blocked). Traffic is not encrypted.
• Using a remote host server. All traffic is then forward through the proxy to that remote host which will then connect to the target server/port. This requires having access to a remote host server which can run the required server software.

Using HTTHost + HHTPort

HTTHost+HTTPort is a free HTTP Tunneling package, including local tunnelling client and remote host server.

Using socat

socat is a command-line utility that establishes two bidirectional byte streams and transfers data between them. It is a very powerful utility that can be used to establish connection between various type of interfaces (TCP/Serial/...).

Manpages are here.

Example of commands to open a local port 143, that maps to a remote IMAP server through corporate proxy:

/usr/local/bin/socat -ly 'TCP4-LISTEN:143,reuseaddr,fork' PROXY:ton.imap.server:143|TCP:134.27.168.36:8080