need help with dynamic DNS updates [SOLVED]

Simon Hobson dhcp at
Tue Mar 14 07:40:58 UTC 2006

Ross Boylan wrote:

>  > >>Mar 10 20:17:32 wheat named[7080]: client view
>>  >>inside: update '' denied
>>  >>Mar 10 20:17:32 wheat dhcpd: Unable to add forward map from
>>  >> to timed out
>>  >
>>  >OK, this tells us a lot. The second line is logged by dhcpd and says
>>  >that it attempted an update, but it timed out. Not overly helpful as
>>  >it tells us it failed (useful in itself) but not why ...
>>  If named gets an update request that is not permitted, it ignores it
>>  and does not reply, hence the requesting process times out.
>Ah.  I thought one referred to the forward and one to the reverse
>update.  Looking more closely, they both look like the forward
>update. (I hope I've got the terms right: forward is from name to IP,
>backward the reverse.)

The trick is to note that in syslog, you get the date & time, the 
hostname (you can log other machines to one syslog so you need the 
hostname to know where the log came from), and the process that was 
running. So the first line clearly comes from named (specifically the 
process running as id 7080), the second line comes from dhcpd - ie 
they are from different programs.

>So when dhcpd's request for a forward update fails, it gives up and
>doesn't try to do the reverse update?

Correct. It only attempts to update the reverse pointer if the 
forward update succeeds OR the client is doing the forward update.


More information about the dhcp-users mailing list