There are many reasons why you might need to check the status of your Domain
Name System (DNS) records. For example, you might need to verify that updates
are correct or troubleshoot issues with accessing a service.
If you're a Cloud DNS user, you can
view your DNS records through the Cloud Control
Panel. In addition, Microsoft® Windows®
nslookup, a built-in tool for checking your DNS records from the
nslookup, open a command prompt window by selecting Start >
All Programs > Accessories > Command Prompt.
To check a specific DNS record, you need to specify the
an optional record type (for example,
TXT), and the host name
that you want to check.
Note: If you omit the record type, it defaults to
The following example shows how to check
A records for rackspace.co.uk:
C:\Users\Administrator>nslookup rackspace.co.uk Server: cachens1.lon.rackspace.com> Address: 18.104.22.168 Non-authoritative answer: Name: rackspace.co.uk Address: 22.214.171.124
The first two lines of output specify the server to which the request
was directed. This server is the default server that your system uses for DNS
The second section gives the name of the record and the corresponding Internet
Protocol (IP) address. However, the answer in this section is
non-authoritative because it originates from a server
(cachens1.lon.rackspace.com) that isn't the root source for those records.
To get an authoritative answer you need to specify the authoritative (primary)
name server at the end of the request.
-type=soa option to tell
nslookup to display the
authoritative name server, as shown in the following example:
C:\Users\Administrator>nslookup -type=soa rackspace.co.uk Server: cachens1.lon.rackspace.com> Address: 126.96.36.199 Non-authoritative answer: rackspace.co.uk primary name server = ns.rackspace.com responsible mail addr = hostmaster.rackspace.com serial = 1415913000 refresh = 3600 (1 hour) retry = 300 (5 mins) expire = 1814400 (21 days) default TTL = 300 (5 mins) ns.rackspace.com internet address = 188.8.131.52
The address labeled
primary name server is the DNS authority for the
If you add the address of the authoritative name server
(ns.rackspace.com) to the first command, the record is now checked
against that name server.
C:\Users\Administrator>nslookup rackspace.co.uk ns.rackspace.com Server: ns.rackspace.com Address: 184.108.40.206 Name: rackspace.co.uk Address: 220.127.116.11
DNS uses caching, which reduces the load on authoritative name servers.
However, as a result, records might be outdated. If the authoritative and
non-authoritative answers differ, you have a cached response from the resolver
name server that you're using. The length of time that a record is cached
depends on its time-to-live (TTL) value. The TTL is a number that is
specified in seconds.
To see how long a record is cached, include the
debug option, as shown in
the following example:
C:\Users\Administrator>nslookup -debug rackspace.co.uk ------------ Got answer: HEADER: opcode = QUERY, id = 1, rcode = NOERROR header flags: response, want recursion, recursion avail. questions = 1, answers = 1, authority records = 2, additional = 2 QUESTIONS: 18.104.22.168.in-addr.arpa, type = PTR, class = IN ANSWERS: -> 22.214.171.124.in-addr.arpa name = cachens1.lon.rackspace.com ttl = 2466 (41 mins 6 secs) AUTHORITY RECORDS: -> 151.138.83.in-addr.arpa nameserver = ns2.rackspace.com ttl = 2466 (41 mins 6 secs) -> 151.138.83.in-addr.arpa nameserver = ns.rackspace.com ttl = 2466 (41 mins 6 secs) ADDITIONAL RECORDS: -> ns.rackspace.com internet address = 126.96.36.199 ttl = 12982 (3 hours 36 mins 22 secs) -> ns2.rackspace.com internet address = 188.8.131.52 ttl = 12985 (3 hours 36 mins 25 secs) ------------ Server: cachens1.lon.rackspace.com Address: 184.108.40.206 ------------ Got answer: HEADER: opcode = QUERY, id = 2, rcode = NOERROR header flags: response, want recursion, recursion avail. questions = 1, answers = 1, authority records = 2, additional = 2 QUESTIONS: rackspace.co.uk, type = A, class = IN ANSWERS: -> rackspace.co.uk internet address = 220.127.116.11 ttl = 279 (4 mins 39 secs) AUTHORITY RECORDS: -> rackspace.co.uk nameserver = ns.rackspace.com ttl = 17465 (4 hours 51 mins 5 secs) -> rackspace.co.uk nameserver = ns2.rackspace.com ttl = 17465 (4 hours 51 mins 5 secs) ADDITIONAL RECORDS: -> ns.rackspace.com internet address = 18.104.22.168 ttl = 15754 (4 hours 22 mins 34 secs) -> ns2.rackspace.com internet address = 22.214.171.124 ttl = 15727 (4 hours 22 mins 7 secs) ------------ Non-authoritative answer: Name: rackspace.co.uk Address: 126.96.36.199
The response includes the following information:
- The first
Got answersection of this example is used to get the
host name of the server from which you are requesting the
In this example, the host name is cachens1.lon.rackspace.com.
- The second
Got answersection relates to your actual request.
HEADERsection contains details about the type of request and
QUESTIONSsection shows that the request was for
ANSWERSsection displays one record with an IP address of
188.8.131.52 and a TTL of 279 seconds (4 minutes 39 seconds).
AUTHORITY RECORDSsection specifies the name servers that
correspond to the domain.
ADDITIONAL RECORDSsection lists
Arecords for the name servers
that are listed in the authority records section.
This response shows that the name server that the client computer uses will
reuse the same
A record for rackspace.co.uk for the next 4 minutes and 39
seconds. If you run the same command on the authoritative name server, you
see the current maximum TTL for the record.
Updated 20 days ago