DDNS not updating host

Sun Feb 10 14:29:34 UTC 2013

We already answered that, "FAILED: Has an A record but no DHCID, not
mine." means there is an A record already there but no TXT record. The
DHCP server/client will not overwrite the record when it already
exists, it will only overwrite if a) the "A" record exists AND b) the
TXT record indicates that the current client is responsible for the
record. If the TXT record doesn't exist then the "b" clause fails.

As Glenn suggested this is to prevent you, for example, calling your
new client mail.company.com and then putting it on the network. If the
DHCP server/client just blindly updated DNS then your actual
mailserver DNS records would be hijacked and everyone would now be
pointing at the new client.

Also your two log snippets don't match in respect to times, if you
want to see what is happening on both DHCP and BIND at the same time
then you will need to match the times. All those logs show is that at
an earlier time the client did update DNS, but there is no indication
on what is happening when dhcpd is saying "Forward map ... FAILED".

Steve

On 10 February 2013 11:34,  <arun.sasi1 at wipro.com> wrote:
> Ok in such a case, why some of laptops are unable to update their DDNS record via DHCP.
>
> I had mention that, I used to get below error
>
> 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)
>
> 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 4:57 PM
> To: Users of ISC DHCP
> Subject: Re: DDNS not updating host
>
> In short you can't, it's a limitation when used by multi-homed
> systems. This is precisely what the TXT record implementation prevents
> (multiple mac addresses updating the same A record).
>
> Steve
>
>
> On 10 February 2013 10:55,  <arun.sasi1 at wipro.com> wrote:
>> 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.
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