How to display a web page without being blocked by a firewall?
I want our application to show an online help page (always up to date) or even a local page. However, it may be blocked by a firewall (Zone Alarm).
By the way, I tested this with Zone Alarm. It blocked access to the local .html file as well as the .asp file on the internet. (Ie, tried to display a page in Internet Explorer and got Zone Alarm dialog asking if I want to allow display
Is there a way to get around this? Perhaps display the web page in a web browser?
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It's actually very unlikely that web traffic is blocked on a firewall (unless you mean the file type is blocked?). However, you may need to use the same proxy that IE uses as direct traffic may be blocked.
The easiest way to do this is to use the high level windows API or IE itself, and HTTP download the latest help file if there is a new one - these mechanisms should be aware of any proxy.
Of course, your users may not be using IE, even if most are. Thus, you may need to tell the user to proxy or auto-configure the proxy in the same way the browser does.
edit: I see you mean the zonal world is part of the problem. yes, this is difficult, as you will either have to get your application "blessed" centrally by those who manage the zone in the customer's organization, or (if there is no centralized management), the user will have to allow the application to communicate. Maybe you need to bite the bullet and make the online help just a website and create your preferred browser via a "execute" url as suggested in another answer.
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If the web browser is not blocked by a firewall, then they will probably open port 8080 for any application and therefore your application should not be blocked.
If the firewall only allowed port 8080 for IE; you need to punch a hole in your firewall in order to use a new browser like firefox or chrome.
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To open a web page using the user's preferred browser (with appropriate proxy and authentication settings), use something like ShellExecute
the URL of the document being loaded. Something like this would do it (where page
is the download url):
HINSTANCE r = ShellExecute(NULL, "open", page, NULL, NULL, SW_SHOWNORMAL);
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