[dns-operations] Truncation query

[Ray Bellis]

I can't find chapter and verse in the RFCs, and I'm trying to confirm
whether this packet returned by the DNS server in my Apple Airport
express is legal.

In my recursive resolve testing app I've asked for a 2k TXT RR, with
EDNS.   The reply has come back with TC=1, QDCOUNT=1, ANCOUNT=1, but
there is no answer in the packet.

000000  ad d2 83 80 00 01 00 01 00 00 00 00 05 6c 61 72
000010  67 65 03 72 63 74 03 69 73 63 03 6f 72 67 00 00
000020  10 00 01

Should the server have set ANCOUNT=0 in this packet for it to be legal,
or should the presence of TC=1 be taken to mean that "all bets are off"
for everything after the question section?

Ray