dhcp

Once in a while all the desktops stop communication with the applications in the LAN and when we configure static IP ( same IP that is assigned by the DHCP server) the desptop works normally and when we again set “take ip from dhcp” gets into problem,

then we defined the scope in another dhcp server and the desktop works normally and restore the old dhcp server the desktop works normaly ..

why it behaves like this .. what is wrong