Failover peer outside pools?

Nicolas Ecarnot nicolas at
Thu Nov 5 09:44:25 UTC 2015


All our subnets are behind routers that have ip helpers, redirecting 
DHCP requests towards 2 dhcp servers in failover peers (we have around 
10 DHCP servers in couples).

In our setup, I just noticed that amongst our hundreds of 
shared-networks using failover peers, some subnets have a strange 
configuration :

I saw that in some rare cases, we have some subnets with *no* pool, thus 
*no* failover setup, where there's just one static reservation declared, 
and it is working.
But I was wondering how it goes?
- when the host is requesting some DHCP traffic, it is broadcasted via 
the router towards 2 DHCP server that have no idea about what the other 
did some hours ago in this subnet
- as the only request is about a static ip, I guess any of both server 
is answering correctly, but not telling the other.

So I'm embarrassed that the router is broadcasting the DHCP traffic to 2 
servers that don't talk (about this particular subnet - there are 
chatting about others).

The documentation seems to imply that failover definition lies only 
inside pools.
I could create a pool just to add failover context, but the same doc 
also states that static reservation should stay outside pools.

Am I missing something?


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