One subnet, two pools, one with a default gateway, the other without

Friesen, Don CITZ:EX Don.Friesen at
Mon Aug 12 19:32:49 UTC 2013

>The problem with groups that you will encounter is that when systems do a followup DHCPINFO 
>request - for device descovery or whatever - which seems to be the modus operandi for the 
>major OS.... The DHCP server will only be able to provide the defaults and not the values 
>that you expect. My experience with this effect is mostly for DNS server values so your 
>results may vary for route info, but the risk is there.
>I tend to include these preferences within the subnet definitions and use secondaries to carve up the network.
>Randall Grimshaw rgrimsha at

  I have encountered the same, but since some of my group defined values are different from the
Dynamic pool values I have had to empty the shared-network and subnet levels of all options
and duplicate them into the pool and group blocks.  This has worked, since it appears that, for my 
cases, the DHCPINFORM does not update network fields that have null responses in them.

   So our IP phones get their network parameters from the pool or group blocks, and the follow-up 
DHCPINFORM issued by the phone software gets it's parameters based on the class/subclass block 
associated with the phone vendor class.

Don Friesen.

More information about the dhcp-users mailing list