DNS error

every 15 minutes to a hour i keep getting this message in my event viewer.
The DNS server has encountered numerous run-time events. These are usually caused by the reception of bad or unexpected packets, or from problems with or excessive replication traffic. The data is the number of suppressed events encountered in the last 15 minutes.
The event ID is 9999 no category is given and it is only a warning. I know from the error that it has something to do with replication but what?