Another support issue I have seen that is becoming fairly common occurs when a website is published through UAG 2010 and an external client tries to download files larger than 10 megabytes. The error which the client sees will be “The page cannot be displayed.” Looking a little closer we also see an “HTTP 500 – Internal server error.” For purposes of recreating the error I used SharePoint 2010 but you could potentially see this error for any website published.
By default UAG sets aside a 10MB buffer for URL filtering. Trying to download a file larger than 10MB will result in UAG rejecting the request and will result in the error seen above.
There are a couple of ways you can get around this, the first is by changing a registry key on the UAG Server.
The registry key is mentioned in this link.
If the key is not there the default value is still 10MB which means the value of the DWORD would be 10240000.
If you wanted to increase this to 50MB you would just use the formula 1024*1000*50 to get a value of 51200000.
After creating or modifying the registry key simply activate the UAG configuration and then do an IISRESET in an administrative command prompt (or reboot the server).
The second method is to configure UAG to Skip Body Parsing for the site which is experiencing the issue. This is configured for the Portal where application is published. Choose “Configure trunk settings”.
Next click the Edit button next to “Do not parse the response bodies to these requests:”
A list of servers will come up. Highlight the server that is having the issue and a list of URLs will show up. These are the URLs that are skipped by default.
Note: The publishing wizard in UAG adds this automatically when you publish your SharePoint site. If the server you are having the issue with is not already there you will need to add it under the Servers list.
I used a tool such as HTTPWatch to figure out what I needed to exclude in my case and it turned out to be .*/_layouts/.*
I added that path to the URLs list on my UAG Server using a RegEx format which UAG requires.
After activating the configuration and doing an IISRESET I am now able to download files larger than 10MB.