Windows 2000 Terminal Server Security

I was able to get straight through Black Ice Firewall. I was connecting to a windows 2000 server running Terminal server. I was connected to the internet and made the connection just by configuring the 32 bit client for terminal server 2000 on my WindowsNT4.0 server. How did the client get through the firewall without a port being opened. Is there a security patch for this.