replication time for dynamic records from primary to secondary servers

Cuttler, Brian R (HEALTH) brian.cuttler at
Thu Apr 1 20:09:26 UTC 2021


I don't think the issue I'm having is related to notify message not being reacted to nor zone transfer requests not being sent to answered.

What I think I'm seeing is DHCP updating the DNS primary, which works correctly, but I don't believe it updates the SOA serial number nor sends a notify message.

When you add a record to a zone, either by # nsupdate or via the transaction (I assume nsupdate protocol) between DHCP and DNS primary does something else need to be configured in order to get that incremental change sent to the secondary? Something that does not normally need to be set?

The issue is not that frequently noticed. The typical problem that crossed by desk looks like this.
 - Someone put a new printer online, it gets an IP from DHCP and asks DHCP to register its "name" with DNS which DHCP does on behalf of our printers
   and desktop computers (we do not allow the end points to create DHCP records).
 - I don't believe this updates the SOA serial number nor generates a Notify message, thought at could be a deficiency in the config.
 - At some point the secondary gets all of the updated records from the primary but in that interval the print server is updated to create a new print
   queue and if it queries the DNS secondary the printer name may fail to resolve.

The answers we have employed are 1) be patient 2) remove the deficient zones files from the DNS secondary and restart the DNS secondary.

Should the incremental update from the DHCP server cause DNS to update the SN and send a notify message?
Is there some other mechanism to update the secondary?


-----Original Message-----
From: Tony Finch <fanf2 at> On Behalf Of Tony Finch
Sent: Wednesday, March 31, 2021 11:43 AM
To: Cuttler, Brian R (HEALTH) <brian.cuttler at>
Cc: bind-users at
Subject: Re: replication time for dynamic records from primary to secondary servers

ATTENTION: This email came from an external source. Do not open attachments or click on links from unknown senders or unexpected emails.

Cuttler, Brian R (HEALTH) via bind-users <bind-users at> wrote:
> We are seeing a delay in the primary DNS server updating the secondary
> and would like to shorten that interval.

This is probably due to NOTIFY messages not working. NOTIFY is the
mechanism that allows primary servers to tell secondaries to get the
latest version of a zone promptly. I wrote some notes on debugging slow
zone transfers a couple of weeks ago:

f.anthony.n.finch  <dot at>
Fair Isle: North 5 or 6, decreasing 3 or 4, then backing northwest 4
or 5 later. Moderate or rough, becoming slight or moderate. Mainly
fair. Good.

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