Offer in a dhcp fo setup with split 255

[Meike Stone]

2011/11/7 Simon Hobson <dhcp1 at thehobsons.co.uk>:
> Meike Stone wrote:
>
>>  > I've configured two dhcpd servers (dhcpd01 and dhcpd02) in a fail over
>>>
>>>  association.
>>>
>>>  The primary is connected directly in the client subnet. The secondary
>>>  is reachable via dhcp relay (ip helper) from the client subnet.
>>>  The primary should answer every time, if available. Therefor the split
>>> is 255.
>>>
>>>  But after a DISCOVER from a client in the client subnet, both server
>>>  answer immediately with a OFFER.
>>
>>  > Is this the correct behavior in a dhcp FO setup?
>
> I've not used failover, but my understanding is that the split value
> controls only how IP addresses are split between the servers - it does not
> control which one answers a client query.

>From manual page:
"The split value determines how many of the leading bits are set to
one. So, in practice, higher split values will cause the primary to
serve more clients than the secondary."

I configured "split 0/255"! Then only one server should answer with a
OFFER if DHCP-FO is in NORMAL state?


> I think there is a min-secs setting (or something like that) which controls
> how quickly a server will respond. As long as the client behaves properly
> and sets the field correctly, the server will not answer before the client
> has already been asking for whatever time you set. Thus setting it to (say)
> 5 seconds one server would give the other server chance to respond and the
> client accept it's offer first.
>

Yes thats called "load balance max seconds", what I set to 3 seconds.
>From manual page:
"The effect of this is that if one of the failover peers gets into a
state where it is responding to failover messages but not responding
to some client requests, the other failover peer will take over its
client load automatically as the clients retry."

So the second server should answer earliest 3 seconds after, and only
I the client don't get a response?!

Kindly regards and thanks,
Meike