Clients not using static host mapping

Hello, 

I am trying to set up a simple network where the EdgeMax Router(WAN 10.218.60.11/LAN 192.168.21.1) is connected to our outisde router (10.218.0.1).  I want the edgemax router and its clients to resolve a hostname to (192.168.21.30).  I've added the entry in the static host mapping and the router resolves it correctly but the clients do not.  Any thoughts would be appreciated.