Nagios: DNS CRITICAL – ‘/usr/bin/nslookup -sil’ msg parsing exited with no address

Scenario: We changed from BIND to Unbound on a smarthost email server. As soon as this was changed Nagios started throwing up a "DNS CRITICAL – '/usr/bin/nslookup -sil' msg parsing exited with no address" . In the following example i've substituted myhost.domain.co.uk for the actual host. Troubleshooting steps:  From the Nagios server i checked the config file: Read More…