DDNS not updating host

Sun Feb 10 10:55:50 UTC 2013

SO I assume, the system go IP via LAN and they tried to renew IP via Wireless too.

So that two interfaces are registering with same host name but TXT got messed up. If this is the case then how to rectify this issue.

________________________________________
From: dhcp-users-bounces+arun.sasi1=wipro.com at lists.isc.org [dhcp-users-bounces+arun.sasi1=wipro.com at lists.isc.org] on behalf of Glenn Satchell [glenn.satchell at uniq.com.au]
Sent: Sunday, February 10, 2013 4:06 PM
To: Users of ISC DHCP
Subject: Re: DDNS not updating host

In this case there is an existing A record, but no DHCID (ie corresponding
TXT) record. So dhcpd will not update hte A record. The assumption is that
this is an existing A record not placed there by dhcpd. eg consider if
someone gave their laptop the same name as your main fileserver.

The way to get things going again is to remove the A record manually, then
when dhcpd next renews the lease it will be able to update DNS and create
both A and TXT records.

As to how it got there, well there are a number of possibilities I can
think of: it could have been created manually, the client could have
created it as p[art of a direct client DNS update, or something got messed
up when the lease expired and dhcpd was not able to remove both the A and
TXT records. There is no requirement that a direct client update will
create the TXT record, eg Windows only creates the A record. This is
purely a mechanism that dhcpd uses.

regards,
-glenn

On Sun, February 10, 2013 8:58 pm, Steven Carr wrote:
> BIND DNS does not support scavenging so something else has to remove
> the TXT entry (TTL does not equal "expiry", TTL is the amount of time
> the record is allowed to be cached for).
>
> Usually this process is handled by the DHCP server and not the DHCP
> client as the DHCP server would be keeping track of the leases. If
> nothing is removing the records then this is why your DNS records are
> not being updated as the existing TXT record is blocking the update.
>
> I would suggest looking at getting the DHCP server to update DNS
> instead of the DHCP client.
>
> Steve
>
>
>
> On 10 February 2013 09:49,  <arun.sasi1 at wipro.com> wrote:
>> Hello Steven,
>>
>> dhclient uses a DHCP-ID to indicate that a DNS record has been updated
>> by a certain client. The DHCP-ID is either provided by the client as a
>> configured value, or a hash value automatically computed over a
>> combination of the FQDN of the host and its MAC address. Currently the
>> DHCP-ID is stored in the DNS (by dhclient) as a TXT record (in lack of a
>> proper DNS record). dhclient will only update the record if it either
>> doesn't exist at all, or if the corresponding DHCP-ID matches. Otherwise
>> it's left as it is. Therefore, if a DNS file contains a static record
>> for a hostname.
>>
>> So I assume DNS must remove the entry, since the TTL value  is taking
>> care by DNS
>>
>> Thanks & Regards,
>> Arun Sasi Venmalassery
>> -------------------------------------------------------------------------------------------------------------------------------------
>> Sr. Engineer - Server Management (UNIX),
>> Wipro Ltd (Dubai) |Mob: +971 566489491 | E: arun.sasi1 at wipro.com
>>
>> ________________________________________
>> From: dhcp-users-bounces+arun.sasi1=wipro.com at lists.isc.org
>> [dhcp-users-bounces+arun.sasi1=wipro.com at lists.isc.org] on behalf of
>> Steven Carr [sjcarr at gmail.com]
>> Sent: Sunday, February 10, 2013 3:00 PM
>> To: Users of ISC DHCP
>> Subject: Re: DDNS not updating host
>>
>> When the DHCP server queries DNS for the TXT record for the client
>> which is wanting to update it can't find the TXT record or the data in
>> the TXT record does not match anything that the DHCP server has added.
>>
>> Try deleting the TXT record for the client and then see if it can
>> update. If that fixes the issue then you need to work out why DHCP
>> isn't automatically removing the added records when the lease expires.
>>
>> Steve
>>
>>
>>
>> On 10 February 2013 08:39,  <arun.sasi1 at wipro.com> wrote:
>>> Hello Team,
>>>
>>> I have DDNS configured in my isc-dhcp server. some of laptops are not
>>> updating with their new Ip address to the DNS server.
>>>
>>> I get below error message from DHCP and DNS
>>>
>>> DHCP
>>>
>>> Feb 10 09:32:02 sd5embinf01 dhcpd: DHCPOFFER on 163.183.40.116 to
>>> 48:5b:39:83:23:ef (OAal-SD05) via 163.183.43.4
>>> Feb 10 09:32:02 sd5embinf01 dhcpd: Forward map from
>>> OAal-SD05.emb.bsl.com to
>>> 163.183.40.116 FAILED: Has an A record but no DHCID, not mine.
>>> Feb 10 09:32:02 sd5embinf01 dhcpd: DHCPREQUEST for 163.183.40.116
>>> (163.183.243.133) from 48:5b:39:83:23:ef (OAal-SD05) via 163.183.43.1
>>> Feb 10 09:32:02 sd5embinf01 dhcpd: DHCPACK on 163.183.40.116 to
>>> 48:5b:39:83:23:ef (OAal-SD05) via 163.183.43.1
>>> Feb 10 09:32:03 sd5embinf01 dhcpd: Forward map from
>>> OAal-SD05.emb.bsl.com to
>>> 163.183.40.116 FAILED: Has an A record but no DHCID, not mine.
>>>
>>> In DNS
>>> Feb 10 06:31:44 gb02embns01 named[16046]: client 163.183.243.131#44006:
>>> updating zone 'emb.bsl.com/IN': update unsuccessful:
>>> OAal-SD05.emb.bsl.com:
>>> 'name not in use' prerequisite not satisfied (YXDOMAIN)
>>> Feb 10 06:31:44 gb02embns01 named[16046]: client 163.183.243.131#51487:
>>> updating zone 'emb.bsl.com/IN': update unsuccessful:
>>> OAal-SD05.emb.bsl.com/TXT: 'RRset exists (value dependent)'
>>> prerequisite not
>>> satisfied (NXRRSET)
>>> Feb 10 06:31:45 gb02embns01 named[16046]: client 163.183.243.131#53081:
>>> updating zone 'emb.bsl.com/IN': update unsuccessful:
>>> OAal-SD05.emb.bsl.com:
>>> 'name not in use' prerequisite not satisfied (YXDOMAIN)
>>> Feb 10 06:31:45 gb02embns01 named[16046]: client 163.183.243.131#59861:
>>> updating zone 'emb.bsl.com/IN': update unsuccessful:
>>> OAal-SD05.emb.bsl.com/TXT: 'RRset exists (value dependent)'
>>> prerequisite not
>>> satisfied (NXRRSET)
>>>
>>> Why this is happening, and what could be the reason for this.
>>>
>>>
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