Windows Azure – Firefox & “Port Restricted for Security Reasons”

I’ve been starting to delve into the world of Windows Azure this week.

After getting the Azure Samples loaded, I tried running one of them (just by hitting F5 in VS) and, as Firefox is my default browser, got a “Port Restricted For Security Reasons” error.

Of course, it worked fine in IE

Here is what to do –

It turns out, that my application was trying to use port 87 on (

Load up Firefox. Type about:config in the address bar, and hit enter. You will get something like the following:


Right click, and click New -> String.

Set the preference name to:

Next, set the value to: 87 (or whatever port your app is using)


7 responses to “Windows Azure – Firefox & “Port Restricted for Security Reasons””

  1. Cutcher Throte avatar
    Cutcher Throte

    This is nowhere near good enough. I can only unban one port at a time? And I have to go through Mozilla’s version of the registry to do it? And even then it’s JUST NOT WORKING? Screw this blatant censorship and steering of users away from content by Mozilla.

    1. Alex avatar

      each to their own i suppose….
      You don’t have to do this frequently, only for high – risk ports like this…

  2. mnrp avatar

    Thanks for the tip.

  3. Steven Woods avatar

    Thanks Alex,
    that port blocking was one of those things that was mildly annoying (a reload would work), but finally frustrated me. Much appreciated!

  4. Jacob Cynamon-Murphy avatar

    Alex, this little issue was getting me down while I was trying to debug my first Azure app in Visual Studio 2010. Thank you for providing this tip – it was a real timesaver!

  5. Spencer Marks avatar
    Spencer Marks

    Hello there webmaster I like your write-up

  6. Lynne Nance avatar
    Lynne Nance

    Hello, like your site very much. I found it on bing will add it to bookmark and come back often again to read and follow. Please continue to do awesome job you do on it.

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