What is "SERVFAIL" mean?

[Nitin.K.]

hi,
       NXDOMAIN indicates that this domain does not exist,
SERVFAIL indicates the domain name server failure to answer the query.

HeePok Lee wrote:

> Hi all!!!
>
> When I use nslookup with debug mode,
> I got a below message.
> But I don't know meaning of "SERVFAIL".
> And I don't know what is difference between "SERVFAIL" and "NXDOMAIN"
> Could you explain about it?
> Thank you!!!
>
> $ nslookup -debug 12.21.2.1
> Server:  ns.dacom.co.kr
> Address:  164.124.101.2
> .
> .
> .
> .
> ;; res_mkquery(0, 1.2.21.12.in-addr.arpa, 1, 12)
> timeout (5 secs)
> timeout (10 secs)
> timeout (20 secs)
> ------------
> Got answer:
>     HEADER:
>         opcode = QUERY, id = 50951, rcode = SERVFAIL
>         header flags:  response, want recursion, recursion avail.
>         questions = 1,  answers = 0,  authority records = 0,  additional = 0
>
>     QUESTIONS:
>         1.2.21.12.in-addr.arpa, type = PTR, class = IN
>
> ------------
> *** ns.dacom.co.kr can't find 12.21.2.1: Server failed
>
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