Neverfail Continuity Engine disables Automatic DNS Registration on the Protected Server

Neverfail Continuity Engine disables Automatic DNS Registration on the Protected Server

 

Summary

This Knowledge base article provides information about the configuration of Automatic DNS registration on a server protected by Neverfail Continuity Engine.

 

More Information

When Installing or Upgrading Neverfail Continuity Engine

Neverfail Continuity Engine recommends that the NICs used for Principal (Public) and/or Channel NIC should have the "Register this connection's addresses in DNS" check box cleared/disabled prior to installing or upgrading Neverfail Continuity Engine to prevent issues with DNS name resolution. If "Register this connection's addresses in DNS" is detected as enabled, an acknowledgeable warning message is issued to inform the user that this feature will be automatically disabled during install/upgrade (if user acknowledges), and to recommend that they verify and make necessary adjustments to the DNS configuration (detailed in the following procedure). 

Note: If the "Register this connection's addresses in DNS is enabled" warning message is acknowledged by the user and Engine installation is continued without performing the necessary DNS adjustments, then there is a potential risk of experiencing server unavailable issues, as a consequence of missing DNS records.
Following procedure must be performed before the acknowledge of the Continuity Engine installation "Register this connection's addresses in DNS " enabled related warning, to prevent any accidental DNS related server unreachable issues after Continuity Engine's installation.
  1. On the Production (Primary) server, before proceeding with Engine installation:
    1. Clear the "Register this connection's addresses in DNS" check box on each Public or Channel NICs.
    2. Trigger the registration of the DNS record. This will remove its associated dynamic Domain Name System (DNS) record(s) from the DNS server. To do this, use one of the following steps, which are listed in the order of preference:
      1. Restart the DNS Client service.
      2. Open a Command Prompt window as administrator, and then run the ipconfig /registerdns command.
  2. On the DNS server:
    1. add static DNS record(s): one for each IP address configured as Public in Neverfail Continuity Engine. This/these records will replace the removed dynamic DNS records.

More information:

  1. https://support.microsoft.com/en-ph/help/2933537/clearing-the-register-this-connection-s-addresses-in-dns-option-does-n

If Enabling "Register this connection's addresses in DNS"  feature after Neverfail Continuity Engine is installed

Neverfail Continuity Engine checks periodically the status of the NICs used for Public and Channel connections. If it detects "Register this connection's addresses in DNS" feature as being enabled, it will automatically disable it and issue a warning to inform the user about this condition.

 

Potential issues with "Register this connection's addresses in DNS"  feature enabled

Channel and Management addresses may get automatically registered in DNS, resulting in clients being unable to connect to the protected application because their DNS queries are resolving to either a Channel or Management address; which may not be accessible from the public network, instead of the Principal (Public) address.

 

The user should review their DNS configuration and identify DNS name servers with zones that are configured for dynamic updates looking specifically for unwanted entries in both the forward and reverse zones that refer to the Neverfail protected cluster name which resolve to either channel or management IP addresses (or the PTR equivalents) and remove them.

Note: In a DR (WAN) environment configured with different Public IP addresses for each site, automatic DNS updating is provided by Neverfail Engine through a dedicated task.

 

Applies To

Neverfail Continuity Engine 8.5 and later

 

KBID-3007


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