Indicates if a DNS response message packet has been truncated due to excessive length.
property TC: Word;
TC is a Word property that indicates if a DNS response message packet has been truncated when the length of the message packet exceeds the maximum permitted on the transmission channel. TC will contain the value 1 when the mesaage packet has been truncated, or the value 0 when the packet contains the entire response issued by the name server.
Messages handled by the UDP-based DNS Resolver are restricted to 512 bytes (not counting the UDP headers). Longer messages are truncated and TC is set to 1 in the header. For this reason, the UDP-based TIdDNSResolver does not implement DNS zone transfers, but is the recommended method for standard queries in the Internet.
TC is represented in a DNS header as a bit field. Changing the value of TC ensures that the appropriate bit field is updated in the DNS header for the message packet.
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