Saturday, January 8, 2011

Automate Internet Proxy Management with PowerShell

The solution is very simple, yet the issue was so annoying to me that I thought to share this. I have a laptop and do work on it on site at my client and when I am at home. When I am in the office connected to my client’s network I need to use a proxy to access the Internet, while usually I do not need a proxy when I am located elsewhere. You normally set up a proxy using browser settings. With Internet Explorer 8 you open a browser, then go to Tools >> Internet Options >> Connections >> LAN Settings. There you configure the proxy parameters. As a part of configuration you can turn the proxy on or off by setting or clearing a Use a proxy server for your LAN check box, and as you switch the proxy the rest of your proxy configuration settings such as exceptions is preserved for you. Great!

My problem was that on almost daily basis I had to open the browser, navigate to settings then check or uncheck that box. I would come to work and forget to go through the steps so my browser would get stuck, and then I would go “oh yeah, I turned the proxy off last night”. Of course the reverse would happen at home… I tolerated this too long because I didn’t expect that a simple solution exists, but it does and here it is:

 HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ProxyEnable key stores a DWORD value, either 1 or 0 to indicate if the proxy is enabled.

So I wrote two 1-line PowerShell scripts and added two shortcuts to them to my Windows taskbar: Enable Proxy, Disable Proxy! Here is how the script to enable proxy looks like:

Set-ItemProperty "HKCU:\Software\Microsoft\Windows\CurrentVersion\Internet Settings" -Name ProxyEnable -Value 1

Then I’ve got excited, and wrote yet another rock star PowerShell script. Here it is:

$matches = @(ipconfig /all | findstr "myclientdomain")
if($matches.Count -gt 0){
    ./EnableProxy.ps1
}else{
    ./DisableProxy.ps1
}

That’s right I am using output of the ipconfig command to determine if I am on the client’s network and if yes then I turn on my proxy. After I have added a scheduled task running at user logon to invoke this script, the quality of my professional life has improved.

4 comments:

  1. I've been meaning to find out how to do this and write this script for about a year now.

    Thanks for doing this and sharing it.

    Jeffrey Snover [MSFT]
    Distinguished Engineer
    Visit the Windows PowerShell Team blog at: http://blogs.msdn.com/PowerShell
    Visit the Windows PowerShell ScriptCenter at: http://www.microsoft.com/technet/scriptcenter/hubs/msh.mspx

    ReplyDelete
  2. Thank you, Jeffrey. I actually had an error in my last script: should use "-gt" instead of ">". Obviously. It worked fine at home because it always forked to the else branch, so I only noticed it at work today. The script is now corrected in the post.

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