Here is a nifty trick to perform a Reverse DNS Lookup on an IP Address that utilizes a web based REST API.

This approach utilizes HTTP GET to do the DNS Lookup via a REST API provided by dns-api.org:

C_TEXT($0) C_TEXT($1;$url_t;$response_t;$thisDNS_t) C_LONGINT($httpStatusCode_li;$a) ARRAY OBJECT($response_oba;0) If (Count parameters=2)    $url_t:="https://dns-api.org/ptr/"+$1    $httpStatusCode_li:=HTTP Get($url_t;$response_t)    If ($httpStatusCode_li=200)       If (Substring($response_t;1;1)="[")          JSON PARSE ARRAY($response_t;$response_oba)          If (Type($2->)=Text array)             For ($a;1;Size of array($response_oba))                $thisDNS_t:=OB Get($response_oba{$a};"value";Is text)                If (Substring($thisDNS_t;Length($thisDNS_t);1)=".")                    // strip trailing dot                   $thisDNS_t:=Substring($thisDNS_t;1;Length($thisDNS_t)-1)                End if                APPEND TO ARRAY($2->;$thisDNS_t)             End for          End if       End if    End if End if

If the method above is saved as UTIL_ReverseDNSLookup then it could be used like this:

ARRAY TEXT(domains_at;0) UTIL_ReverseDNSLookup ("123.45.67.89" ;->domains_at)

The code above will populate the domains_at text array with any PTR records found for 123.45.67.89