When a client requests a webpage from a URL such as http://www.linkedin.com/ an HTML document is downloaded. This HTML document requires the browser to download additional files and elements (files such as *.gif, *.js, etc.). Very often the source of these files is a web server that is on a different domain than the original linkedin.com domain. If these other domains are blocked by WebMonitor's policies the webpage may still be shown but may be missing elements.
In order to prevent this, all the different domains that the website is using need to be allowed. There are 2 options:
- Add them to the Always allowed list (GFI WebMonitor 2015 add the item to the Whitelist)
- Add them as an exception in the policy that is blocking them
GFI recommends the 2nd choice if at all possible. This is because adding them to the Always allowed list will allow ALL FILES from ANY web server(s) in those domains to bypass the GFI WebMonitor's policies, including its virus scanning engines. Web servers on the internet are often compromised by hacking organizations to deliver their trojans and other nefarious programs. If you are certain the domain's web servers are trustworthy and secure you can use the first option.
In order to check which connections are launched for a particular webpage, perform the following:
- Open GFI WebMonitor console
- Browse to Dashboard > Activity
- From the top right click the drop down for period: and select the current day
- From the lower part, click Users and select the user you are currently testing with
- Click Event Log and find the time period which this page was accessed to confirm which domains are being blocked
You should look for other domains that are being blocked at the same time. Then switch to the Filtered Only view to see which policy blocked them. Then you can add these as an exception to the policy that blocked them.