Read a `dig` Answer

Rung 1 of the ladder asks "does the name resolve?" — and dig is the tool that answers it. But dig prints a wall of text, and only four parts of it matter on call. Learn to read those four, and you can read any answer dig ever gives you. First, make sure the tool is even there:

dig example.com

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12345
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; QUESTION SECTION:
;example.com.            IN  A

;; ANSWER SECTION:
example.com.        3600    IN  A   93.184.216.34

;; Query time: 24 msec
;; SERVER: 8.8.8.8#53(8.8.8.8) (UDP)

Four things, top to bottom, and nothing else matters yet:

status: NOERROR

The query succeeded. This is the DNS equivalent of a green light — the name was looked up and an answer came back.

ANSWER SECTION

What the name maps to. Here example.com → the A record 93.184.216.34. No answer section, or ANSWER: 0, means nothing resolved.

3600 (the TTL)

How many seconds this answer may be cached before it must be looked up again. A big number means "you'll keep seeing this even after it changes."

SERVER: 8.8.8.8#53

Which resolver gave you this answer. The most-skipped line and the most important — the next lesson is built on it.

Run it now against a name you actually care about at work. Next: that SERVER: line — why "DNS is fine" is a meaningless sentence until you name the resolver.