What are all the flags in a dig response

digdomain-name-system

dig responses return flags in the comments section:

$ dig example.com +noall +comments

; <<>> DiG 9.8.3-P1 <<>> example.com +noall +comments
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29045
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

On the last line here, there are flags:

flags: qr rd ra;

What are all the possible flags that dig has?

Here's a list of the ones I've found so far:

Best Answer

I am using RFC 1035 as source, keeping to the sequence from there, regardless if you already mentioned it in your question.

  • QR specifies whether this message is a query (0), or a response (1)
  • OPCODE A four bit field, only valid values: 0,1,2
  • AA Authoritative Answer
  • TC TrunCation (truncated due to length greater than that permitted on the transmission channel)
  • RD Recursion Desired
  • RA Recursion Available
  • Z Reserved for future use. Must be zero

There were two more DNSSEC-related flags introduced in RFC 4035:

  • CD (Checking Disabled): indicates a security-aware resolver should disable signature validation (that is, not check DNSSEC records)
  • AD (Authentic Data): indicates the resolver believes the responses to be authentic - that is, validated by DNSSEC
Related Topic