Duplicated leases, same IP and same MAC

carlos jorge carlosd2002 at hotmail.com
Wed Sep 21 13:52:58 UTC 2011

> >  > The second lease entry had an "atsfp" entry added to it; which I
> >>  seem to recall is related to failover.
> >So if it's normal, and like in memory the DHCPd had 2 lease for the 
> >same IP and MAC (tested via omshell), how can i use OMAPI/omshell to 
> >get a lease in this condition?
> Are you using failover ? If so, then first thing would be to upgrade. 
> 3.1.3 is very old and I think you'll find the release notes for later 
> versions make mentions of bug fixes and improvements related to 
> failover.

I just was able to found release notes to these versions on site (there are  more?):

DHCP 4.2


Client lease records are recorded at most once every 15 seconds. 
 This  keeps the client from filling the lease database disk quickly on 
very small  lease times. [ISC-Bugs #19660]


  [ISC-Bugs #19615] update the includes in dhcpctl/dhcpctl.3 to be more correct

The second one is to vague but the first one is related to the memory dump to dhcp.leases file right? I m testing some code that i have done that uses OMAPI and i tested it in home with dhcpd 4.1 (no failover) and i never face this behavior (more than one lease with the same IP and MAC). Now i m testing my code in a real network infra-structure (more traffic) that as the V3.1.3 with failover, but i m not the owner or responsible for the network so i can't upgrade :(

it could be due the fact that in V4.1.2 the dump/clean of leases in memory is done more often (15 seconds)  then in V3.1.3 (don't know the time)? and so its more unlikely to catch such situation?
Do you have any other idea?


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