create file <client-name>, containing ifconfig-push 10.160.81.x 10.160.81.y, where x and y are taken from
[1,2] [5,6] [9,10] [13,14] [17,18]
[21,22] [25,26] [29,30] [33,34] [37,38]
.
.
.
[241,242] [245,246] [249,250] [253,254]
Note: only needed for machines which require a fixed addr
Note: need to be careful not to double-allocate