No Option 43 in DHCP ACK

Jason Bailey jbailey at
Mon Jul 13 18:42:29 UTC 2015

Hi all,

I'm trying to troubleshoot a problem with DHCP option 43. I've defined 
the vendor option space and declared the vendor specific options per the 
vendor's documentation, but I'm not getting any results.

The device (DHCP client) is sending options 53 (request), 60 (vendor 
class ident), 61 (client identifier), 43 (vendor specific info) , 55 
(parameter request list), among a few others. Option 55 includes 43 
(vendor specific info) in addition to the usual items (like subnet mask, 
router, etc). The server is sending an ACK, but it doesn't include any 
of the option 43 items I've defined.

In my DHCP server config, I've defined "option space XYZ" and "option 
XYZ.item code 1 = ip address". I've also configured defined 
"vendor-option-space XYZ" and "option XYZ.item" inside the 
subnet declaration (the entire subnet has been created entirely for the 
same type of devices, so there's no need to match only a certain type of 
devices (i.e. device class))

dhcpd -t doesn't complain about any issues in my config file, and there 
are no issues in the log (I'm using 'log-facility local7').

I'm at a loss at the moment, so any help is greatly appreciated. I'm 
running ISC DHCP 4.1.1 on CentOS 6.6.


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