Reverse dns packet with tc bit = 1
I received a DNS packet with a PTR query, and an additional record. The additional record's data looks like garbage (name uknown, type and class unknown, negative TTL etc.)
The truncated bit (TC) is 1.
Is this packet valid? Should the DNS ignore the invalid data because of the truncated bit?
Truncated means the answer was too large for UDP and the server should retry in TCP mode. If the answer was over 512 bytes and no DO bit (EDNS), TCP should be tried next under normal circumstances. If TCP is blocked/not supported, you essentially get the error but no answer.