The client listing part of my munin.conf is shown below
[revor.fionavar.dd] address revor.fionavar.dd use_node_name yes [mornir.fionavar.dd] address mornir.fionavar.dd use_node_name yes [darien.fionavar.dd] address darien.fionavar.dd use_node_name yes
You may also be interested in a full munin.conf example