Failover and Option Values

sthaug at sthaug at
Tue May 11 20:23:09 UTC 2010

> I'm finding that option 82 values are sometimes not shared between
> failover servers. It seems that sometimes it shows up on both servers,
> but in a lot of cases, only one server will have this value. This is
> causing a problem in my current situation. Is there a fix for this?

Known missing feature, no current fix. See for instance the message at

and the followup message from Dave Hankins of ISC.

The basic problem is that the option 82 info is not transmitted in the
failover messages between the servers. So your basic DISCOVER will be
transmitted to both servers by the relay agent (and both servers will
have the option 82 info). But on renewal the client will typically
unicast its request directly to one server. The other server gets the
necessary info about the lease via the failover protocol, but at the
moment this does not include the option 82 info.

Steinar Haug, Nethelp consulting, sthaug at

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