Multiple streams support DDNS updates instead of a single-thread DDNS queue.
Multi-threaded DDNS updates enhance the resiliency of DHCP by allowing various streams to support DDNS updates, instead of creating a single-thread DDNS queue, which adversely affects DHCP performance. Multi-threaded DDNS is automatically enabled and can't be configured from the Address Manager user interface.
Attention: Messages in DDNS queue might be lost upon server reboot or service restart
Currently, a limitation exists whereby accumulated messages in the DDNS queue might be lost upon reboot of the DNS server or restart of DNS service. In some cases the DNS server responds with ‘SERVFAIL’ for a short period of time. During this brief delay (2-3 seconds) some messages in the DDNS queue might be lost. This is due to the lack of a delay for messages stored in the DDNS queue in the event that messages are returned from the DNS server.
- This limitation applies to managed DNS Servers.
- For more information, refer to article 15046 on BlueCat Customer Care.
You must configure the following DNS options for DDNS to function:
- Allow Dynamic Updates—takes an ACL, match list, or TSIG key as an argument. Only
addresses or keys matched on the list are allowed to send updates to the server for that
zone.Attention: Dynamic DNS updates in an xHA cluster environment must be configured using the physical IP addresses (not a virtual IP address) of the active and passive nodes.
You must configure the following DHCP Service options for DDNS to function:
- DDNS Updates—indicates whether the server should attempt a DDNS update when the lease is confirmed.
- DDNS Domain Name—the domain name appended to this client’s host name to form an FQDN. This is also the name of the zone to be updated with this client’s record.
- Client Updates—indicates whether client updates should be used to maintain DDNS
records for this client. When selected, the client updates its own DNS record on the server. If
not selected, the DHCP server performs the update. This option is required for DDNS.Note: DDNS Updates are enabled by default in Address Manager and this can cause a slow or unresponsive DHCP service because the DHCP service runs in a single thread leading all DHCP lease updates are processed serially. In order to avoid this issue, disable DDNS Updates manually. refer to Adding DHCPv4 service deployment options to disable DDNS updates.
You may configure the following DHCP Service options to enhance DDNS functionality:
- DDNS TTL—an integer value from 0 to 4,294,967,295 in seconds indicating the default TTL for DDNS records.
- DDNS Host Name—the host name for DDNS updates for the client. If no value is specified, the zone creates a name for the records.
- DDNS Reverse Domain Name—the reverse domain name appended to this client’s host name to form a reverse record. By default, this value is in-addr.arpa.