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Thread: IE7 Bypass Proxy issue - .Net redirect

  1. #1
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    IE7 Bypass Proxy issue - .Net redirect

    Hi folks

    This is one of those issues that involves several different technologies which makes it very hard to find the correct place to ask for support.

    I suspect what I really need here is someone who understands the inner workings of IE7, but also someone who understands .Net (certainly server-side HTTP redirecting) and about Proxy Bypass settings.

    Here's the situation:

    I've written a simple server control which sits on one of our company's web pages. Depending on a couple of querystring values the server control may call
    PHP Code:
    HttpContext.Current.Response.Redirect 
    to a 3rd party URL (i.e. not hosted on our server).

    It just so happens that this web page is serving an RSS feed, and the 3rd party site is serving our feed with some additional bits 'n' bobs that we like.

    So, our in-house testing team browse along to the page and on the first visit we deliberately don't redirect them. So they sign up to our RSS feed using IE7's built-in RSS reader.

    I then flick a switch in the database to force the redirect to occur. In theory, the tester's RSS reader should pick up the feed from the redirected location. This works in IE6, Outlook and FireFox, and even with my IE7, but not his!

    His feed doesn't update and he receives the message "Internet Explorer was unable to update this feed"

    So, after careful investigation we find that he has a modified host file with a specific IP for our website, and he has listed this site in the "Bypass Proxy" settings.

    So, what appears to be happening is that the RSS engine in IE7 is seeing the subscribed URL and realises that he wants to go to a specific server for it. Upon going to that server, the server wants to redirect his browser, but the browser has specific instructions to only go to the server that he specified in his host file. So, it can't do the external request and therefore can't get the external feed data.

    That's what appears to be happening. However, it's very difficult to find out what really is going on - is it something in IE, or is it something at the server's end?

    In any case, when he removes the host file entry and the Bypass Proxy entry, it all works just fine and dandy!

    Can anybody help? Or even point me towards the correct Microsoft support page?

    Thanks
    ....Rodders

  2. #2
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    I can't think of any particular KB's about this one, but one thought I have is can the server the control is running on access the internet, and also access this remote hosted page? if so, couldn't the page you render just go out and retrieve the contents of the target page for the end user?
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  3. #3
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    Cheers chazzy.

    I think what you're suggesting is possible and would be a good solution. However, the solution I have already works. It is only when our tester inadvertantly had his host file and proxy bypass set up that the issue was encountered.

    What I'm trying to do is understand the inner workings of IE, to try and get to grips with why it was happening. It seems that the browser is saying

    "OK, that URL you gave me is in my list of ones to bypass the proxy for so I'll trot along to the server you told me about in your host file."
    "Hey, the server is trying to send me to a different URL but I remember you wanted me to only use this one server so I'll try and get that site there."
    "Nope, that site ain't on that server so you can have this error message instead."
    Last edited by Rodders; 10-03-2008 at 05:54 AM.
    ....Rodders

  4. #4
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    .......whereas, in other browsers and even Outlook it appears to be saying

    "Hey, the server is trying to send me to a different URL and this one isn't in your list, so I'll use the proxy to find that one.......oh, here it is."
    ....Rodders

  5. #5
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    have you considered changing the security level in IE?
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  6. #6
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    this type of "problem" is repeatable on a lot of pages and is the result of the security settings in browsers (the Outlook browser included). the only work around is to cache the feed on your server and then the linking will behave. the other advantage of using a cache is that you don't request a new connection to the feed every time the page is loaded (set the cache refresh to something reasonable to show the feed updates) and you can keep an old cache file in case the feed is offline or if the http_request fails for some reason.

    you cannot control how the user sets up his browser!

  7. #7
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    Could any of you enlighten me about the particular security settings that cause this behaviour? And can someone explain what is going on inside the brain of IE with these settings on?

    I don't think the issue is one that we need to be worried about, but it caused some interest and head scratching in the office.

    Thanks
    ....Rodders

  8. #8
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    go to technet.microsoft.com. there are a few references to this type of problem. the security and policy settings are the responsibility of the individual user of the browser. the defaults are fairly high, but don't cause too many problems. Paranoia is the most common reason that people set security levels to the max and policies to excessively restrictive levels. At the corporate level this usually takes place due to bad advice from the "son-in-law" IT guru.

    "Yesterday I couldn't spell IT and now I are one!"
    ...but stupidity is terminal.

  9. #9
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    I have several trials with proxy services. Nowdays i am using https://www.iwasel.com/en/ to bypass proxy and unblock websites. It is very reliable and encrypts your connection out of country so the censors can't see what i am doing.

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