Mine

subnet 192.168.190.0 netmask 255.255.255.0 {
        option domain-name-servers      200.16.1.194, 200.16.2.194;
        option domain-name              "pucp.edu.pe";
        option broadcast-address        192.168.190.255;
        option routers                  192.168.190.134;
        option subnet-mask              255.255.255.0;
        #option option-128              code 128 = string;
        #option option-129              code 129 = text;

        if substring( option vendor-class-identifier, 0, 9 ) = "PXEClient" {
                filename "/ltsp/i386/pxelinux.0";
        }
        else {
                filename "/ltsp/i386/nbi.img";
        }

        option root-path "/opt/ltsp/i386";

}

group {
        #use-host-decl-names     on;
        next-server             192.168.190.134;
        #filename        "/lts/2.6.17.8-ltsp-1/pxelinux.0";

        host ws001 {
                hardware ethernet       00:16:76:3A:AE:7D;
                fixed-address           192.168.190.201;
        }

        host ws002 {
                hardware ethernet       00:0D:60:20:1D:6E;
                fixed-address           192.168.190.202;
        }

        host ws003 {
                hardware ethernet       00:19:D1:E9:B6:41;
                fixed-address           192.168.190.203;
        }
}