Many users feel that this is a part of IRC when it really happens outside of any DALnet servers. DALnet cannot be responsible for these activities. It is the responsibility of the user to protect themselves against these attacks, and to have the necessary software to get information on the nuker. IRC Operators will not track down and remove nukers since logs can be faked very easily.
For more information about DoS attacks, visit http://docs.dal.net/docs/annoy.html#4