Failover stability (peer holds all free leases)
Keith.Lawson at sjhc.london.on.ca
Wed Jul 5 14:55:28 UTC 2006
>>>Glenn.Satchell at uniq.com.au 07/05/06 6:33 am >>>
>>Date: Tue, 04 Jul 2006 14:05:13 -0400
>>From: "Keith Lawson" <Keith.Lawson at sjhc.london.on.ca>
>>To: <dhcp-users at isc.org>
>>Subject: Failover stability?
>>I'm just wondering what the state is of master/slave peer failover. Is
>>failover stable enough to be used in a production environment now?
>>I've been testing using 3.0.4 one one subnet and I'm running into a
>>scenario where the master load balances a request to the slave. The
>>slave then ignores the request and logs a "peer holds all free leases"
>>message. I've been reading through the mailing list archives and
>>indications are that these problems are supposed to be resolved in
>>but that doesn't seem to be the case.
>I've been running failover for over 5 years (since 3.0.1rc6) on a site
>with 3500 PCs and 4500 IP phones, so I think it's perfectly
>satisfactory for production use.
Here's the scenerio I seem to be running into while testing:
- win2k pc gets a lease
- manually release that lease
- when I attempt to renew, primary server gets DHCPREQUEST and sends a
DHCPACK. Then I see a DHCPDISCOVER message from the client that gets
load balanced to the slave server.
- The slave server sees a DHCPREQUEST for an IP that the master holds so
sends a DHCPNAK message.
Shouldn't the client accept the first DHCPACK and never send the
Both DHCP servers are on the same subnet and both are in as helper
addresses right now.
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