dhcpd.conf for dynamic dns

Simon Hobson dhcp1 at thehobsons.co.uk
Tue Mar 20 08:02:32 UTC 2007

S Kalyanasundaram wrote:

>Oh cool now the dhcp talks to dns!.  I think while updating the dns 
>there will be some TXT data written in lease file as well. Better 
>delete the lease file and touch it again and try it. ( I hope you 
>are not in the productive environment).

NO, don't do that.

>"Chow Chi Ho
>(FP&HO)" <chchow at cabletv.com.hk> wrote:
>>  There is a response from dhcp server to dns server after I 
>>removing  "option
>>  fqdn.server-update on;"
>>  and add "ddns-hostname = concat ( suffix .........)); "  to the pool.
>  > But I got another problem  "  if 00e06f584da4.example.com IN A 
>rrset doesn't
>>  exist add 00e06f584da4.example.com 43200 IN A RRset already
>>  exists. "  , log from dhcp server.
>>  and the dns server " 'rrset does not exist' prerequisite not satisfied
>  > (YXRRSET)  "

That should be pretty self explanatory - it means that the record 
"00e06f584da4.example.com A" already exists.

This server will NOT overwrite an existing record that it did not put 
there itself - this is to stop someone naming their machine the same 
as one of your servers and hijacking connections to it !

Delete the record and try again, the dhcp server will attempt to 
update again next time the client renews. If that is successful then 
you will see the A record and an additional TXT record which is a key 
put there so that the DHCP server knows that it created the record 
and so it can safely delete or replace it.

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