As I recently mentioned, Microsoft has discontinued and will be terminating their Microsoft Reputation Services (MRS) cloud URL categorization service on or shortly after December 31, 2015. Today, Microsoft released additional information vital to TMG administrators everywhere who are still relying on this service for URL filtering. Specifically, what happens with TMG once Microsoft officially turns off MRS and it is no longer available?
First, any firewall rules that rely on URL categorization to allow traffic will fail closed. That is, they will block all traffic. Second, any rules using URL categorization to deny traffic will fail open and allow that traffic instead. Finally, there is potential performance degradation that may occur with TMG after the service is disabled by Microsoft.
What to do?
First, update any TMG firewall rules that use URL Categories or URL Category Sets. You can replace them with Domain Name Sets or URL Sets, if desired. Next, disable the use of URL filtering in TMG by opening the TMG management console, right-clicking Web Access Policy and choosing Configure and then URL Filtering. Uncheck the box next to Enable URL Filtering and then click Ok.
Finally, consider a replacement solution for TMG’s URL filtering. There are a number of solutions available, both on-premises and cloud-based, that are capable replacements. The Zscaler solution is highly effective, and if you’re looking for a low-buck alternative, consider something like OpenDNS. There are many more, I’m sure.
As a reminder to anyone out there still using the URL filtering feature of their Forefront TMG 2010 firewall, the Microsoft Reputation Services (MRS) service, which provides URL categorization for TMG, will no longer be supported after December 31, 2015. After this date, Microsoft will cease updating their URL categorization database. In addition, there are no guarantees from Microsoft that the service will be available in any form, so customers still using this service are strongly encouraged to look for alternative solutions.
For many organizations, this means migrating to another platform entirely, which is not a bad idea considering that TMG is nearly six years old now. Alternatively, it is possible to replace TMG’s web filtering component. This can be done on premises by using integrations from various third-party vendors, or by using a cloud-based solution such as Zscaler.
Regardless which path you take, you have just over one month to identify and implement another URL filtering solution. Good luck!
I’m not certain what the reason for this categorization is for, but based on past experience it may have to do with Twitter services running on a shared hosting provider that previously included services that were identified as phishing related. To resolve this issue, open the Forefront TMG management console, highlight the Web Access Policy node in the navigation tree, then click Configure URL Category Overrides in the Tasks pane and move the URL pattern *.twitter.com/ to the Online Communities category.