Well actually we found that with rdp there are 2 issues. One you can have multiple connection to the server and sometimes we might get a couple people working on an issue with the machine and both are logged in and neither knew the other was working on it. Second we could limit to 1 session, but we would end up stealling the session from each other. So we decided to take an alternate route which works well. We disable rdp and use vnc, you can password protect and encrypt VNC so you can have a secure connection and you can connect and see if anyone is doing anything on the machine. VNC can get a little slow but for our senerio it works, it also gives a single way to access machines, don't have to remember to use the VI client or an IP KVM session. Some people get confuse and/or don't understand the difference.