NTP is configured in the central site core switch to get time from master clock on the internet. Switches at central site sync off the core switch fine. My first remote site router syncs off the core switch fine. However, my three remote LAN switches, I have pointed to remote router, and will not sync off of that. (They can PING the router). Is there some type of vaiance that I need to configure for NTP to allow me to Cascade NTP references?