ping resolves all hostnames on an internal LAN to an external ip

Hello all,

I’m havin windows 2003 sp1 as a DC, i’ve got 5
machines that are acting as clients, the prb is
that whenever i try to ping any of the machines
using their hostnames, the reply comes frm some
ip address that is out of the network like in
mycase i’m gettin a reply frm 69.64.155.124….
plz, guide me, how to resolve this issue…