Adding Networks to Failover setup

Glenn Satchell Glenn.Satchell at
Tue May 1 12:33:47 UTC 2007

>Date: Tue, 1 May 2007 10:17:59 +0400
>From: "Abu Abdulla alhanbali" <montaqa at>
>To: dhcp-users at
>Subject: Adding Networks to Failover setup
>I'm trying to add networks to the failover setup as follow:
>- Add the network to the primary dhcpd.conf
>- restart the primary server while the secondary server is running
>- Add the network to the secondary dhcpd.conf
>- restart the secondary server while the primary server is running
>Then both servers are hanging and logging this from both of them in a loop:
>pool response: 0 leases
>pool 22f768 172.18.140/24  total 6  free 5  backup 1  lts -2
>pool 10a418  total 2  free 2  backup 0  lts -1
>peer dhcp-failover: Got POOLREQ, answering negatively!  Peer may be out of
>leases or database inconsistent.
>and whenever I shutdown one of them:
>DHCPDISCOVER from 00:0c:29:c4:56:05 via ce0: peer holds all free leases
>So what is the correct way to add networks to the failover setup. I don't
>want to have a shortage in the service. what is better; configure them to
>have failover or having two identical servers and manually failover them (in
>this case the server will depend on the ping command to discover if the IP
>is free or not to resolve IP conflicts).
>Greatly appreciate your help,
>Abu abdulla,

Typically you should add the networks to the secondary first, restart
it, wait for the secondary to return to normal mode, then do the
primary. That way when the primary tries to send the network
information to the secondary that system knows about the new networks.
At least that's the way I've always done it.


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