New Public IP address in Plesk is not updated on DNS zones on slave DNS server(s)

Symptoms

• After changing the Public IP address to a new one at Plesk > Tools & Settings > IP Addresses, the Slave DNS Manager extension does not update the current DNS zones on the slave DNS server(s) with the new IP:

  # nslookup example.com 203.0.113.4
  Server: 203.0.113.4
  Address: 203.0.113.4#53
  Name: example.com
  Address: 203.0.113.2

  Note: In the above example, 203.0.113.4 is the slave DNS server; the new Public IP address changed at Plesk (Master) is 203.0.113.3, which is assigned to example.com. However, when checking the domain zone against the slave DNS server, example.com still resolves to the old IP, which is 203.0.113.2.

• The zone file on the slave DNS server still shows the old IP address as the master:

  # named-nzd2nzf /var/cache/bind/_default.nzd
  ...
  zone "example.com" { type slave; file "bot.example.com"; masters { 203.0.113.2; }; };

• Both Plesk and the Slave DNS server run on the same internal sub-network that runs behind a NAT, at Google Cloud. The servers are synced via Slave DNS Manager using their internal IP addresses.

Cause

Bug in the Slave DNS Manager extension with ID EXTPLESK-929, which will be fixed in future product updates.

Resolution

As a workaround, remove the DNS zone files on the slave DNS server and manually disable and re-enable the DNS for the domains at Plesk to recreate the zone files with the new public IP address.