Why do the commands dig and nslookup sometimes print different results?

~$ dig facebook.com

; <<>> DiG 9.9.2-P1 <<>> facebook.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6625
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

; EDNS: version: 0, flags:; udp: 512
;facebook.com.            IN    A

facebook.com.        205    IN    A

;; Query time: 291 msec
;; WHEN: Sun Oct  6 17:55:52 2013
;; MSG SIZE  rcvd: 57

~$ nslookup facebook.com

Non-authoritative answer:
Name:    facebook.com

2 Answers 2


dig uses the OS resolver libraries. nslookup uses is own internal ones.

That is why Internet Systems Consortium (ISC) has been trying to get people to stop using nslookup for some time now. It causes confusion.

  • 31
    Actually the decision to obsolete nslookup has been reverted, at least in the nslookup provided by ISC. Source: kb.isc.org/article/AA-00496/0/BIND-9.9.0a3-Release-Notes.htm (Entry # 1700)
    – ata
    Commented May 12, 2014 at 22:54
  • 3
    @ata Link you provided doesn't exist anymore.
    – QMaster
    Commented Apr 21, 2019 at 12:24
  • Had a weird situation today where nslookup would not return any result (would time out) but using systemd-resolve worked very well. This was a new one for me and I will likely use systemd-resolve in the future instead of nslookup.
    – Jeff
    Commented Apr 23, 2019 at 1:16

For a while nslookup was being reported as a deprecated application and should not be used anymore.

The output even warned you of this:

Note: nslookup is deprecated and may be removed from future releases. Consider using the 'dig' or 'host' programs instead. Run nslookup with the '-sil[ent]' option to prevent this message from appearing.

excerpt from http://cr.yp.to/djbdns/nslookup.html

Do not use the ancient nslookup program. Whatever you're trying to do, there's a better way to do it. Even the BIND company, which maintains and distributes nslookup, says ``nslookup is deprecated and may be removed from future releases.''

However in the release notes from Bind 9.9.0a3 there is an entry (#1700) which states the following:

1700.   [func]      nslookup is no longer to be treated as deprecated.
                    Remove "deprecated" warning message.  Add man page.

The Wikipedia page also states this:

As of BIND 9.9.0a3, nslookup has apparently been resurrected ("nslookup is no longer to be treated as deprecated"). (The Internet Systems Consortium had previously deprecated nslookup in favor of host and dig for some time.)

So it would seem that nslookup is perfectly fine to use along with dig. In addition to the 2 tools using different resolvers, there are things that are easier to do in dig vs. nslookup, though nslookup is generally the easier of the 2 tools to use day to day.

Also dig's output is typically easier to parse in scripts or in command line usage.

  • How about host? Since it is also mentioned in the quote, I assume that it is the same as dig and nslookup? In other words, the mechanism is the same, only syntax (command and output) difference? Commented Apr 3, 2023 at 7:41

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