Meaning of logmessages

Friesen, Don LCTZ:EX Don.Friesen at
Tue Sep 27 14:13:07 UTC 2011

>> 	As I recall, and I believe as is confirmed by a message from
>> 	ISC which won't leap out of my mail archive just now, the
>> 	difference is significant, and as follows.
>> 	The first (with 'on') is a response to DHCPREQUEST;
>> 	the second (with 'to'), to DHCPINFORM.
>> 	As you probably know, REQUEST is used for address acquisition or
>> 	renewal in order to establish or extend the client's connection
>> 	to the network, while INFORM is used to request other (perhaps
>> 	application-specific) configuration parameters.
>Thank you!
>That was exactly the information I was looking for.

   This might be a good place to make an observation about the contents of the DHCPACK that is sent in response to a DHCPINFORM, as compared to one sent in response to a DHCPREQUEST.  The one sent in response to a DHCPINFORM contains only the options found in the subnet and shared network configurations.  If you have overridden any of these options in a group (for a static reservation) or pool (for a dynamic range), those are not sent.  So when a workstations gets initially configured due to the DORA, at some time later, when an INFORM goes out, it's options may change.

   This was of significant to us due to a set of workstations that were being directed to a reserved set of DNS servers, and a special gateway.  They existed in a shared network where all the other workstations were our standard default.  I had written the configurations to place all the options in the shared network, and the special options into the group configuration.  The workstations would function for a few hours, then fall apart after the INFORM.  I had to move the default options into the pool clauses and duplicate them into the group clauses.

Don Friesen
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Enterprise-Wide Application Services, Corporate Application Services
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