so many lease records for one lease

[Luc T.]

lease 192.168.31.120 {
  starts 0 2007/01/21 20:21:50;
  ends 0 2007/01/21 21:21:50;
  binding state active;
  next binding state free;
  hardware ethernet 00:15:00:23:ee:1a;
  uid "\001\000\025\000#\356\032";
  client-hostname "PC172323126029";
}
lease 192.168.31.120 {
  starts 0 2007/01/21 20:22:36;
  ends 0 2007/01/21 21:22:36;
  binding state active;
  next binding state free;
  hardware ethernet 00:15:00:23:ee:1a;
  uid "\001\000\025\000#\356\032";
  client-hostname "PC172323126029";
}
lease 192.168.31.120 {
  starts 0 2007/01/21 20:22:37;
  ends 0 2007/01/21 21:22:37;
  binding state active;
  next binding state free;
  hardware ethernet 00:15:00:23:ee:1a;
  uid "\001\000\025\000#\356\032";
  client-hostname "PC172323126029";
}
lease 192.168.31.44 {
  starts 0 2007/01/21 20:23:00;
  ends 1 2007/01/22 20:23:00;
  binding state active;
  next binding state free;
  hardware ethernet 00:19:e3:03:90:17;
  uid "\001\000\031\343\003\220\027";
}
lease 192.168.31.44 {
  starts 0 2007/01/21 20:23:00;
  ends 1 2007/01/22 20:23:00;
  binding state active;
  next binding state free;
  hardware ethernet 00:19:e3:03:90:17;
  uid "\001\000\031\343\003\220\027";
}
lease 192.168.31.120 {
  starts 0 2007/01/21 20:23:35;
  ends 0 2007/01/21 21:23:35;
  binding state active;
  next binding state free;
  hardware ethernet 00:15:00:23:ee:1a;
  uid "\001\000\025\000#\356\032";
  client-hostname "PC172323126029";
}
lease 192.168.31.120 {
  starts 0 2007/01/21 20:23:35;
  ends 0 2007/01/21 21:23:35;
  binding state active;
  next binding state free;
  hardware ethernet 00:15:00:23:ee:1a;
  uid "\001\000\025\000#\356\032";
  client-hostname "PC172323126029";
}
   
   
  why are there so many records for the same ip, e.g. 31.120 and 31.44 in the above example?

             
  Luc