DNS and authoritative answers
Written on 13 November 2013, 05:37pm
A simple trick about nslookup that I learned while reading the Smashing Magazine’s free preview of their Book #4
To start, the full syntax of nslookup is:
nslookup [-option] [hostname] [server]
When you run
nslookup [hostname], it’s your local DNS server that answers the query. This answer is non-authoritative.
With an additional step, you can get the local name servers of the hostname:
nslookup -type=ns [hostname]
Using one of these local DNS servers, you can query again:
nslookup [hostname] [local_name_server]. This answer is authoritative.
$ nslookup www.smashingmagazine.com Server: 126.96.36.199 Address: 188.8.131.52#53 Non-authoritative answer: Name: www.smashingmagazine.com Address: 184.108.40.206 $ nslookup -type=ns www.smashingmagazine.com Server: 220.127.116.11 Address: 18.104.22.168#53 Authoritative answers can be found from: smashingmagazine.com origin = a.regfish-ns.net mail addr = postmaster.regfish.com... $ nslookup www.smashingmagazine.com a.regfish-ns.net Server: a.regfish-ns.net Address: 22.214.171.124#53 Name: www.smashingmagazine.com Address: 126.96.36.199
To clean the DNS cache, use
Paul Tero – How To Fix The Web: Obscure Back-End Techniques And Terminal Secrets
From the same author – Introduction to DNS: Explaining The Dreaded DNS Delay
Written by Dorin Moise (Published articles: 256)