How to check DNS accuracy

Owned by Andrew Parlette
Last updated: Sept 27, 2013
1 min read

Use these steps to verify that forward and reverse DNS lookups are working for a network node.

Step-by-step guide

  1. From a command prompt, run nslookup

  2. To check forward lookup:

    1. Type the name of the host using the fully qualified domain name.

      nslookup
      > bray.dev.tricerat.com
Server:		jerry.dev.tricerat.com
Address:	192.168.2.10
 
Name: 		bray.dev.tricerat.com
Address: 	192.168.2.76

    2. Verify that the address returned is correct.

  3. To check reverse lookup:

    1. Type the name of the IP address.

      nslookup
      > 192.168.2.76
Server: 	jerry.dev.tricerat.com
Address: 	192.168.2.10
 
Name: 		bray.dev.tricerat.com
Address: 	192.168.2.76
    2. Verify that the host name returned is correct.

 

Advanced Tips

If you have access to the DNS server:

  • Know the correct IP address from DHCP or from the node itself.
  • Make sure that the host is listed only once in the forward lookup zone.
  • Make sure that the IP address is listed only once in the forward lookup zone (as an A record).
  • Make sure there is a PTR record for the host and it is correct in the reverse lookup zone.
  • Make sure there is only one PTR record for the IP address in the reverse lookup zone.