I've just installed PRTG to monitor the traffic going over my WAN link and I've noticed that I have a lot of traffic between my local server and a few of my remote servers.
The port is 524 which is NCP as far as I can find and it is generating about 25MB of data every hour, at about 55kBps.

I've seen some people say you can block it, and some people say you need it for eDirectory.
Can I block it, or is there some way of bringing the traffic down to a more reasonable amount?