QueryClass is a read-only Word property that represents the QClass used for querying resource records for the specified DomainName. QueryClass is read from the header for the DNS response packet when TIdDNSResolver parses the query results. 

Currently, the TIdDNSResolver implementation does not support all aspects of the DNS protocol, and includes the following limitations: 

• The DNS query class field is limited to examining resource records for the IN (Internet) class only. CS (CSNet), CH (CHAOS), and HS (Hesiod) are not supported at this time.