DDNS - single transaction for A record deletion and creation not updating timestamp

[sssd-bot]

Cloned from Pagure issue: https://pagure.io/SSSD/sssd/issue/3654

• Created at 2018-03-02 01:04:23 by silae
• Closed at 2018-03-02 03:13:08 as Invalid
• Assigned to nobody

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Utilising Dynamic DNS (DDNS) with SSSD is not updating the timestamp for A records.
PTR records are updating the timestamp without issue.
The cause of this issue is because only a single transaction is used for the deletion and creation of the A record, while the PTR record is split into 2 transactions.
This behaviour is identical when performed manually through nsupdate.
Only after splitting the transaction in 2, does the timestamp of the A record update.
This is a big issue when scavenging is enabled.

DNS: Windows Server 2012 R2
Client: CentOS 7
Domain: Active Directory
SSSD: sssd-1.15.2-50.el7_4.8.x86_64
bind-utils: bind-utils-9.9.4-51.el7_4.2.x86_64

My assumption is that the Windows DNS evaluates the end result of a transaction in comparison to the current configuration and applies that end result, rather than literally following every instruction to the letter.
In the case of an A record, the end result is identical to the current configuration of the DNS server (except for the timestamp), so it doesn't make any changes.

Comments

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Comment from silae at 2018-03-02 03:12:41

This is most likely expected behaviour, due to the norefresh behaviour of the Windows DNS server:
"When a DNS record is created by a new client, the NoRefresh interval is in effect. When the client dynamically updates its DNS information in this situation, the client's DNS time stamp is not updated until the Refresh interval takes effect. This behavior prevents the replication of lots of DNS objects in the Active Directory directory service."
https://support.microsoft.com/en-us/help/932464/how-dns-dynamic-updates-work-together-with-the-dns-aging-and-scavengin

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Comment from silae at 2018-03-02 03:13:10

Metadata Update from @Silae:

• Issue close_status updated to: Invalid
• Issue status updated to: Closed (was: Open)