Logging DHCP lease duration in seconds

[Glenn Satchell]

Hi Alp

lease-time shows the remaining time in the lease, not the total time.

This is from the dhcp-eval man page:

     lease-time

       The duration of the current lease - that is,  the  differ-
       ence  between the current time and the time that the lease
       expires.

regards,
-glenn

On Sat, October 3, 2015 6:51 am, Denis Laventure wrote:
> The client will renew the lease at half the max-lease-time. So seeing 150
> sec for a 300 sec lease seems normal.
>
> Hi,
>
> I have an easy question I believe, I want to log DHCP lease durations
> given to clients, I tried the following, however it appears most of the
> time, logs are showing half of the lease duration.
>
> log(info, concat( "IP: ", binary-to-ascii(10, 8, ".", leased-address), " ;
> ", "leasetime:", binary-to-ascii(10,32,"",encode-int(lease-time,32)) ));
>
> I have set the following lease time values for a pool:
>
> subnet 172.16.2.0 netmask 255.255.255.0 {
>   option routers 172.16.2.1;
>   pool {
>     failover peer "failover-partner";
>     default-lease-time 300;
>     min-lease-time 300;
>     max-lease-time 300;
>     range
172.16https://www.dibbssm.net/GroupFiles/Group167/Documents/Cubs/E1_Cub_Fun_In_the_Snow.pdf.2.10
172.16.2.250;
>   }
> }
>
> And this configuration produces an output like this:
>
> Oct  2 14:34:44 mercan dhcpd: IP: 172.16.2.127 ; leasetime:155
> Oct  2 14:37:10 mercan dhcpd: IP: 172.16.2.127 ; leasetime:154
> Oct  2 14:37:13 mercan dhcpd: IP: 172.16.2.127 ; leasetime:297
> Oct  2 14:39:37 mercan dhcpd: IP: 172.16.2.127 ; leasetime:156
> Oct  2 14:42:03 mercan dhcpd: IP: 172.16.2.127 ; leasetime:154
> Oct  2 14:44:28 mercan dhcpd: IP: 172.16.2.127 ; leasetime:155
> Oct  2 14:46:53 mercan dhcpd: IP: 172.16.2.127 ; leasetime:155
> Oct  2 14:49:18 mercan dhcpd: IP: 172.16.2.127 ; leasetime:155
> Oct  2 14:49:54 mercan dhcpd: IP: 172.16.2.127 ; leasetime:264
> Oct  2 14:50:47 mercan dhcpd: IP: 172.16.2.127 ; leasetime:247
> Oct  2 14:51:18 mercan dhcpd: IP: 172.16.2.127 ; leasetime:269
>
> How can log the precise lease durations, would be great if anyone has any
> suggestions?
>
> Thanks in advance.
> Alp
>
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