其他問題

1. IP 重複，在 DHCP server 刪除重複的 IP：

   [root@e517nat ~]# vim /var/lib/dhcpd/dhcpd.leases
   [root@e517nat ~]# grep 192.168.1.154 -A5 /var/lib/dhcpd/dhcpd.leases
   lease 192.168.1.154 {
     starts 5 2015/10/30 13:14:02;
     ends 5 2015/10/30 13:24:02;
     tstp 5 2015/10/30 13:24:02;
     cltt 5 2015/10/30 13:14:02;
     binding state active;
   --
   lease 192.168.1.154 {
     starts 5 2015/10/30 13:18:53;
     ends 5 2015/10/30 13:28:53;
     cltt 5 2015/10/30 13:18:53;
     binding state active;
     next binding state free;
   --
   lease 192.168.1.154 {
     starts 5 2015/10/30 13:23:23;
     ends 5 2015/10/30 13:33:23;
     cltt 5 2015/10/30 13:23:23;
     binding state active;
     next binding state free;
   --
   lease 192.168.1.154 {
     starts 5 2015/10/30 13:27:19;
     ends 5 2015/10/30 13:37:19;
     cltt 5 2015/10/30 13:27:19;
     binding state active;
     next binding state free;
   --
   lease 192.168.1.154 {
     starts 5 2015/10/30 13:31:07;
     ends 5 2015/10/30 13:41:07;
     cltt 5 2015/10/30 13:31:07;
     binding state active;
     next binding state free;
   --
   lease 192.168.1.154 {
     starts 5 2015/10/30 13:36:04;
     ends 5 2015/10/30 13:46:04;
     cltt 5 2015/10/30 13:36:04;
     binding state active;
     next binding state free;