2023-09-20
UPDATE: host is way better, use that:
$ host razzi.abuissa.net
razzi.abuissa.net is an alias for pages.sr.ht.
pages.sr.ht has address 173.195.146.139
dig is a command line dns utility.
Its output is hard to parse but the alternatives are no better.1
Here’s the basic usage:
$ dig razzi.abuissa.net
; <<>> DiG 9.18.12-1ubuntu1.1-Ubuntu <<>> razzi.abuissa.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 33156
;; flags: qr rd ad; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available
;; QUESTION SECTION:
;razzi.abuissa.net. IN A
;; ANSWER SECTION:
razzi.abuissa.net. 0 IN CNAME pages.sr.ht.
pages.sr.ht. 0 IN A 173.195.146.139
;; Query time: 0 msec
;; SERVER: 172.30.0.1#53(172.30.0.1) (UDP)
;; WHEN: Wed Sep 20 01:00:52 CDT 2023
;; MSG SIZE rcvd: 104
Wow that’s a lot of output! The only part I really care about is the answer section.
The lines you’ll want to be scanning for are:
;; ANSWER SECTION:
razzi.abuissa.net. 0 IN CNAME pages.sr.ht.
pages.sr.ht. 0 IN A 173.195.146.139
Confusingly, queries with no results omit the answer section entirely:
$ dig some.nonexistentdomain
; <<>> DiG 9.18.12-1ubuntu1.1-Ubuntu <<>> some.nonexistentdomain
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 59662
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;some.nonexistentdomain. IN A
;; AUTHORITY SECTION:
. 3600 IN SOA a.root-servers.net. nstld.verisign-grs.com. 2023092000 1800 900 604800 86400
;; Query time: 70 msec
;; SERVER: 172.30.0.1#53(172.30.0.1) (UDP)
;; WHEN: Wed Sep 20 01:10:01 CDT 2023
;; MSG SIZE rcvd: 126
If you take the time to read from the top, you’ll see ANSWER: 0.
So you can scan for that when you make a query.
As an alternative to reading through that whole mess,
you can use the +short option to get just the answer:
$ dig +short razzi.abuissa.net
pages.sr.ht.
173.195.146.139
$ dig +short some.nonexistentdomain
$
In that second example above, there’s no answer, so there’s no output.
Helpfully, the excellent vim editor knows how to interpret dig output:
$ dig razzi.abuissa.net > dig.txt
$ vim dig.txt
(shows colorized output)
We can use vimcat to colorize the output directly to stdout:
$ dig razzi.abuissa.net | vimcat
; <<>> DiG 9.18.12-1ubuntu1.2-Ubuntu <<>> razzi.abuissa.net
;; global options: +cmd
# ...
# I don't have syntax highlighting on here but it is colorized!
https://github.com/isc-projects/bind9/tree/main/bin/dig
(dig is part of the BIND dns suite.)
drill has the same output format. dog, though it looks cool, is unfortunately unmaintained. nslookup doesn’t show CNAMEs by default, though you can get it from nslookup -q=cname. ↩