I am currently working for a customer that only allows internet access through their proxy server. Sometimes I need to change these settings during the day if I visit multiple customers. This currently means changing both the settings in Internet Explorer and in the 'servers' SVN config file (which is an alternative for using TortoiseSVN, located in %APPDATA%\Subversion on Windows 7).
The proxy I use at the moment doesn't require authentication. But a 'normal' HTTP/HTTPS proxy could require authentication using username/password. So an option 'Authentication required' is definitely needed, after which you would need to set your username/password.
However, I'm not sure of the type of authentication that is communicated with the proxy server. Some proxies simply use Basic or Digest authentication over HTTP, but I know that Microsoft Proxy server might require NTLM (or Windows desktop/domain) authentication.
I would very much like the option to 'fast switch' between different proxy configurations. Saving the proxy configuration in the project settings might be useful. However, authentication credentials shouldn't be saved, because they will probably differ between team members. Both depend on the current network details, which can change during the day.
See also IETF RCF's number 2068 and 2617 on HTTP/1.1 and HTTP Authentication.
Hope this helps!
Jonathan van Alteren - FlowFabric
You should take a look at this example:
I think a lot of parameters are covered there.