The official seed nodes of the node network are considered to be a part of the whitelist.
So as to avoid synchronizing the data on a node with other nodes that may have been compromised, or are unsafe in any manner, a node can always choose to synchronize with the official whitelisted seed nodes of Ontology.
This can be achieved by using the following command when synchronizing a node-
./ontology --reservedfile=./peers.rsv --reservedonly
peers.rsv file contains the whitelist details.