Dell VxRail: VxRM health-check fails for dnslookup

This health check looks on VxRail Manager for DNS errors when doing a lookup of vCenter (VC), and node addresses. It also checks that each nameserver, listed in the VxRM configuration, is working correctly.
This health-check can produce any of the following results:

#========================#======#=========#====================================================================#==============#
|  Hostname / Category   |Status  Dell_KB |  Warnings or Failures, unless tests Passed                         ; Product S.N. |
#========================#======#=========#====================================================================#==============#
| VxRM                   | Failure 189764 | dnslookup: DNS lookups resulted in errors on: clust2-vcsa.any.local              .|

The Database  tables of VxRail Manager contain a mixture of IP addresses, partial names and Fully Qualified Domain Names (FQDN). In order to cross reference and verify these tables, DNS must be working correctly and DNS is critical for the VxRail upgrade process.

• For Warning, the result indicates the DNS lookup test failed for one the nameservers listed in the VxRail manager configuration. If this is the only DNS related error, then it is probably the secondary nameserver that is incorrect.
• For Failure, the result shows a list of name servers that reported forward DNS lookup errors. These would be recorded when obtaining the IP addresses for the nodes and vCenter, as part of the overall VxRM health-check.

Note:

• A mismatch of reverse DNS lookup results in a Fail.
• In-family Upgrade health check profiles do not test reverse lookups.
• Health check for clusters with external VC, do not Warn or Fail for vCenter reverse lookups.

For the best practices of VxRail Networking setup, please refer to VxRail Network Planning Guide.
Note:

• It is recommended that DNS settings on VxRail Manager, vCenter and ESXi (and other VxRail components) should be the same.
• DNS errors are likely to be the root cause of other health check failures. Fix existing DNS errors first and then re-run health checks to see if other issue remains.

It is recommended that the DNS settings on VxRM are also consistent across a VxRail environment. This may require ensuring that the VxRM database and other places match (see test 'dns_xref').  

2022-08-10 07:50:34-INFO     [dnslookup] Testing DNS fault count and reverse DNS test
2022-08-10 07:50:34-INFO     [dnslookup] Nameserver xxx.xxx.xxx.xxx checked successfully
2022-08-10 07:50:34-INFO     [dnslookup] Nameserver xxx.xxx.xxx.yyy checked successfully

2022-08-13 21:28:55 - INFO [dnslookup] Testing DNS fault count and reverse DNS test
2022-08-13 21:28:55 - ERROR [dns_fqdn_ip] R.Lookup gethostbyaddr [Errno 1] Unknown host, for 11.22.33.44
2022-08-13 21:28:55 - DEBUG [dns_fqdn_ip] Socket gethostbyname_ex for 11.22.33.44
2022-08-13 21:28:55 - INFO [dns_fqdn_ip] gethostbyname_ex returning FQDN 11.22.33.44 & IP 11.22.33.44
2022-08-13 21:28:55 - ERROR Command response 1: DNS fault count and reverse DNS test  ->
2022-08-13 21:28:55 - WARNING [dnslookup] nslookup using nameserver 132.171.52.48, failed