This solution applies to all Barracuda SSL-VPN units, all firmware versions.
You may encounter a web forward that works on multiple browsers but may give 404 errors when using IE8 or IE9. This may be due to a setting where Internet Explorer is seeing a minor HTTP error and will display a standard 404 whereas the other browsers will see the error and then continue in displaying the page properly.
To disable this feature navigate on Internet Explorer to TOOLS, INTERNET OPTIONS, ADVANCED, and un-check the Show Friendly HTTP error option.
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