Cannot Telnet from Windows 2000 Client

We have a few old Unix boxes that we have to telnet or ftp to from time to time. We can telnet to them from a Windows NT workstation with no problem.
However, we cannot telnet from a Windows 2000 client. It tries to open a connection on port 23, and then eventually gives a message that the connection failed.
I know that Microsoft made major changes to telnet between NT and 2000.