How to Restrict Access to Terminal Servers
After finally completing my Group Policy re-write for Windows 7 this week I have gone back to working on the plans for our migration to Exchange 2010. Currently we do use an Exchange 2003 server but only a few users are on it and it is only there to provide compatibility for a couple of specialised programs that are on our Terminal Servers. With the move to Exchange for all users possibly the biggest change will be that now all users have a Windows user account potentially allowing them access to the Terminal Servers when they shouldn’t have any.
In order to do this you could make use of the builtin group called ‘Remote Desktop Users’ which aslong as your using Windows 2003 R2 should have been setup when you installed the Terminal Servers role and by default has permission to connect remotely to any Terminal Server.
It is also possible to customise which users and groups can connect remotely to a Terminal Server so you make your life easier and reuse existing groups to control access, or setup multiple groups if you wanted to limit certain users from connecting to particular Terminal Servers. To do this you can either edit the Local Security Policy on each Terminal Server or apply the changes via Group Policy, the option you are looking for to set this via Group Policy can be seen below (the Local Policy method is also very similar to this and should be easy enough to find):
Enable the 'Allow log on through Remote Desktop Services' Option
Inside this you can add all the users and groups who should have remote access.
While this may seem like all that is needed and while all the users and groups specified can now logon to the Terminal Servers you apply this to you will likely also find that infact *any* user can still login to the Terminal Servers. To correct this we need to make one final change as by default anyone in the Users group can access the server due to the ‘Allow log on locally option’.
Remove the Users group from the 'Allow log on locally' option
While you might be concerned about the warnings given in the ‘Explain this’ tab advising you to not remove users, if you read the relevant section on the link provided it explains that it is safe to do this aslong as you dont remove important users from the list and aslong as users who should have access are granted permission to do so elsewhere.
Hopefully if this has all worked you now have a Terminal Services environment where only those users explicitly allowed can gain access.
