Linux – Some clients aren’t updating using dhcpd’s “ddns-update-style interim” with Windows dns servers

dhcpdhcp-serverlinux

I am using dhcpd 3.0.5 and Windows 2008 R2 for dns. I have "ddns-update-style interim;" set and the Windows server is set to allow unauthenticated updates. Most of the time this works great, but occasionally I'm coming across computers that aren't resolving the hostname to the correct IP address. When I look at dns, there is an A record for the wrong ip, but no TXT record (so dhcpd must not have set it). Not surprisingly the dhcpd logs for that hostname will show "Has an A record but no DHCID, not mine."

Does anyone have any idea how these A records got in there? I'm thinking the client somehow got it in there before dhcpd was able to set it. Is there some way to prevent this? Is there any way to make dhcpd update a record even if it does not have a TXT record? If the client is creating the A record, then it is also not updating itself, but that's not surprising because that seems to be common and is the reason I want dhcpd to do the updates in the first place.

Also, it would be helpful if anyone knew of a way to script deleting an A record and then force dhcpd to retry updating the record (without having to go to the client and send another dhcp request)?

Best Answer

In the interim schema you cannot ignoring txt records because of idea of this schema.

See dhcpd.conf INTERIM DNS UPDATE for consolution.

You need to delete txt records with a records because dhcpd cannot'update a record which the server did not create by logic of this update schema.

Or you can use ad-hoc schema. But ad-hoc is deprecated. I can't say that you really can use it.

First of all you can use clear zone, then dhcpd will populate this zone with settings of hosts in you dhcpd.conf.

Afterall you can add custom A records, which is never update by dhcpd because they don't have a correspond TXT records.

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