Is it possible to check how much time is left before a nameserver like will update its records from my nameserver?

  • The OpenDNS CacheCheck tool lets you force an update before TTL. – Nic Feb 24 '12 at 5:17

Using dig you can check the TTL of a record - like so:

; <<>> DiG 9.7.3 <<>> @ www.serverfault.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 3937
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

;www.serverfault.com.       IN  A

www.serverfault.com.    1800    IN  CNAME   serverfault.com.
serverfault.com.    1800    IN  A

;; Query time: 88 msec
;; WHEN: Thu Feb 23 23:15:23 2012
;; MSG SIZE  rcvd: 67

Specifically, you'll want to pay attention to the values in the answer (1800 in this case)

www.serverfault.com.    1800    IN  CNAME   serverfault.com.
serverfault.com.    1800    IN  A

1800 is the number of seconds until the TTL expires and the record is refreshed on the nameserver (

If you run the command a few times, you'll see the TTL number go down, so as of the time of writing this, the TTL is now like so (1659 sec)

www.serverfault.com.    1659    IN  CNAME   serverfault.com.
serverfault.com.    1659    IN  A
  • 3
    @Greatestswordsman Keep in mind that the server you're querying isn't necessarily at the same place in its TTL timer as every server behind; there are many anycasted nodes, and which you query depends on your location. One timer running down doesn't mean it'll immediately refresh everywhere; you need to wait for your record's full TTL time. – Shane Madden Feb 24 '12 at 5:22
  • A good place to see a general geographical sitrep of DNS updates is to use a site such as 'whereisitup.com' (I have no relation) – thinice Feb 24 '12 at 6:23

For Windows (natively) you can use nslookup.

C:\>nslookup -debug www.serverfault.com

Got answer:
         opcode = QUERY, id = 4, rcode = NOERROR
         header flags:  response, want recursion, recursion avail.
         questions = 1,  answers = 2,  authority records = 0,  additional = 0
        www.serverfault.com, type = A, class = IN
    ->  www.serverfault.com
        canonical name = serverfault.com
        ttl = 1791 (29 mins 51 secs)**
    ->  serverfault.com
        internet address =
        ttl = 1791 (29 mins 51 secs)**

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