= (Web) Proxy by SSH =

<<TableOfContents>>

To get Web access to the I-MATH intranet webserver it is possible to set up a SOCKS SSH proxy channel. This setting is not persistent, start it when you need it.

The proxy configuration can be done:

 * on the OS - ''not described here''.
 * via commandline - described here for ''Google Chrome'' and ''Opera''.
 * inside the browser via GUI - described here for ''Firefox''.

== SSH Proxy ==
 * Use SSH
  * Linux & Mac OS X: preinstalled.
  * Windows: https://www.howtogeek.com/336775/how-to-enable-and-use-windows-10s-built-in-ssh-commands/

 * Open a terminal and start the SSH Socks connection (I-MATH password):
 {{{
ssh -C -D 1080 <I-MATH account>@ssh.math.uzh.ch
}}}

 * This terminal won't be used anymore, but it has to be '''open as long as the proxy is in use'''!

== Browser ==
To use the I-MATH internal DNS Server (necessary to get access to hostnames that are only known inside of I-MATH), use the SOCKS5 protocol '''incl. DNS forward'''.

For Google Chrome or Opera, '''open a second terminal''' and type the following command.
||Browser ||Command ||
||Google Chrome (see also [[https://wiki.math.uzh.ch/public/ProxyBySsh#Advanced_Setup:_Google_Chrome_Proxy_Switch|advanced]]) ||Linux: `google-chrome --proxy-server="socks5://localhost:1080"`<<BR>>Mac OS X: `/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --proxy-server="socks5://localhost:1080"` ||
||Opera ||Linux: `opera --proxy-server="socks5://localhost:1080"`<<BR>>Mac OS X: `/Applications/Opera.app/Contents/MacOS/Opera --proxy-server="socks5://localhost:1080"` ||

 * Firefox
  * There is no official option '-proxy-server' for the command line
  * Start firefox, open 'settings', navigate to 'network' > ''see screenshot''

{{attachment:ff-proxy.png}}

== FAQ ==
 * Q: Can I configure Google Chrome / Opera via GUI like Firefox
  * A: yes - just check the 'network' seetings.

 * Q: Why should I start Google Chrome / Opera via command line?
  * A: This is a very quick way to use the proxy. If you do not need it, start the browser via mouse.

 * Q: Can I automate the steps?
  * A: yes. A small bash script should do the trick: 
  {{{#!sh
#!/bin/bash

nohup google-chrome --proxy-server="socks5://localhost:1080" & ssh -C -D 1080 <I-MATH account>@ssh.math.uzh.ch 
}}}

 * Check [[ssh#Working_with_SSH_Keys|SSH Keys]] to setup password less SSH login.

 * Q: in Firefox I don't like to toggle the proxy on/off all the time - is there a better way?
  * A: Create an additional profile 'proxy'. Start Firefox via Terminal `firefox -P`, create the profile, use it and do the proxy config there.

== Advanced Setup: Google Chrome Proxy Switch ==

Install and configure the Google Chrome extension [[https://chrome.google.com/webstore/detail/proxy-switchyomega/padekgcemlokbadohgkifijomclgjgif?hl=en|SwitchyOmega]] to automatically switch proxy for certain URLs. 

Configurations: {{attachment:switchyOmega_proxy.png}} {{attachment:switchyOmega_autoswitch.png}}