dynamic dns cleanup?

[Cuttler, Brian (HEALTH)]

This is a dhcpd/dynamic dns interaction question, but the question is I think really a dhcpd question.

 

I have a printer that was in “this” building, which uses dynamic dhcp to register DNS entries, this worked as expected, address assigned, Forward and Reverse records created. All good.

 

We have now moved the printer to one of our other building, which does NOT use dynamic DNS. The printer was assigned a new IP address (in the range assigned to that building, according to the helper addresses in the network router), that part is all good, worked as expected.

 

I was wondering about cleanup of the original DNS entries, the ones in the dynamic range in building #1. The entry looks like hri12028.esp122.wadsworth.org (printer tag/name, subnet/range, network name). Will that at some point go away on its own, or get over written?

 

Will it be removed when the dhcp entry for that zone expires, or when the IP is ultimately reassigned?

Or will I need to manually remote the DNS entry if I want to have it ‘go-away’?

 

While I await your advice, I will lock down the new IP in the range for other building (I know, I shouldn’t really have to, but…) and assign it DNS entries at the new address.

 

Note that the other building does not use subnet names, so there will be no conflict, other than the CNAME I created (tag CNAME tag.esp122.wadsworth.org) which greatly simplifies printer access from the user desktop.

 

I guess with my setup, once the second (through 5^th) buildings to dynamic DNS I will only have to update the CNAME entries, unless I can figure out how to get rid of them.

 

Thank you,

Brian

 

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[Nicolas C.]

On 2015-06-25 21:47, Cuttler, Brian (HEALTH) wrote:

> This is a dhcpd/dynamic dns interaction question, but the question is
> I think really a dhcpd question.
>
> I have a printer that was in "this" building, which uses dynamic dhcp
> to register DNS entries, this worked as expected, address assigned,
> Forward and Reverse records created. All good.
>
> We have now moved the printer to one of our other building, which does
> NOT use dynamic DNS. The printer was assigned a new IP address (in the
> range assigned to that building, according to the helper addresses in
> the network router), that part is all good, worked as expected.
>
> I was wondering about cleanup of the original DNS entries, the ones in
> the dynamic range in building #1. The entry looks like
> hri12028.esp122.wadsworth.org (printer tag/name, subnet/range, network
> name). Will that at some point go away on its own, or get over
> written?
>
> Will it be removed when the dhcp entry for that zone expires, or when
> the IP is ultimately reassigned?
>
> Or will I need to manually remote the DNS entry if I want to have it
> 'go-away'?

When the DHCP assigns the address, it keeps some info in the
dhcpd.leases file (host name, IP address, client-id, hardware address,
content of the forward/reverse/TXT records, etc.). When the lease of the
client expires, the DHCP use this information to perform the DNS
cleanup.

So, if everything is correctly configured, the DNS entry will go away
automatically at the end of the lease.

Nicolas C.
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[Cuttler, Brian (HEALTH)]

Nicolas,

Thank you very much, that is what I was hoping, and it is really nice that everything has been thought through and incorporated into the design.

Never did figure out why so many DNS entries got deleted on me a few weeks back, lost entries for active systems which was disturbing. Disabled "update-optimization" and have not no repeats of the issue. A little more DHCPD/DNS traffic, but that is the only downside.

Thanks very much,
Brian


-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Nicolas C.
Sent: Thursday, June 25, 2015 4:47 PM
To: Users of ISC DHCP
Subject: Re: dynamic dns cleanup?

On 2015-06-25 21:47, Cuttler, Brian (HEALTH) wrote:

> This is a dhcpd/dynamic dns interaction question, but the question is
> I think really a dhcpd question.
>
> I have a printer that was in "this" building, which uses dynamic dhcp
> to register DNS entries, this worked as expected, address assigned,
> Forward and Reverse records created. All good.
>
> We have now moved the printer to one of our other building, which does
> NOT use dynamic DNS. The printer was assigned a new IP address (in the
> range assigned to that building, according to the helper addresses in
> the network router), that part is all good, worked as expected.
>
> I was wondering about cleanup of the original DNS entries, the ones in
> the dynamic range in building #1. The entry looks like
> hri12028.esp122.wadsworth.org (printer tag/name, subnet/range, network
> name). Will that at some point go away on its own, or get over
> written?
>
> Will it be removed when the dhcp entry for that zone expires, or when
> the IP is ultimately reassigned?
>
> Or will I need to manually remote the DNS entry if I want to have it
> 'go-away'?

When the DHCP assigns the address, it keeps some info in the dhcpd.leases file (host name, IP address, client-id, hardware address, content of the forward/reverse/TXT records, etc.). When the lease of the client expires, the DHCP use this information to perform the DNS cleanup.

So, if everything is correctly configured, the DNS entry will go away automatically at the end of the lease.

Nicolas C.
_______________________________________________
dhcp-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/dhcp-users
_______________________________________________
dhcp-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/dhcp-users