Failover and pools with single machines

Tina Siegenthaler tina at
Fri Dec 15 14:01:24 UTC 2006

Am 14.12.2006 um 16:52 schrieb Simon Hobson:

> Tina Siegenthaler wrote:
>>> Failover won't work with such small pools. However, since you will
>>>  only have one client/pool then you could simply replicate the  
>>> config
>>>  and NOT use failover. The client will get the same address  
>>> regardless
>>>  of which server it took the lease from, and no other client will  
>>> get
>>>  the same address from the other server.
>>>  You would still need to use failover on the general use pools  
>>> though.
>> Does this mean I can just use the same config file (or that part of
>> it with the single-host pools) on 2 dhcp servers at the same time?
>> Won't they get each other in the way?
> Ordinarily, having two independent servers offering the same
> addresses would be a disaster looking for somewhere to happen. It
> will work in this case because you have pools with exactly one
> address which can be leased to exactly one client - so you can't have
> the same address offered to two different clients.
>> So, if I understand this
>> correctly, a host will issue a broadcast and then take the IP address
>> from the first dhcp server that responds. And it doesn't matter if
>> there is a second dhcp server which would also be able to assign the
>> host an address, since it's already got one. Right?
> Near enough - technically the client is allowed to see what offers it
> gets and choose between them (how is not defined, but for example it
> could choose the one that gives it the most options it asked for). In
> practice, I don't think anyone has found a client that doesn't just
> accept the first offer !

OK, I set the servers up that way and it seems to be working fine  
(well -  running for five minutes now, but I hope it'll stay that  
way). I just have one more minor question about the failover peer  

failover peer "abc": Is "abc" the name of the peer of the server, or  
the name of the server itself? Somehow this isn't clear from the  


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