DNS Lookup, Reverse DNS Lookup, Domain Configuration Check and IP Address Calculators

Domain Configuration Check

This article relates to the Domain Configuration Check tool. The Domain Configuration Check is a free online tool which performs a comprehensive check of your domain's DNS, email and other configuration.

Simply enter your domain name (eg. example.com) and let the Domain Configuration Check tool start gathering its results. To get started, go to the Domain Configuration Check.

Specific Name Server Configuration Tests - Part 1

SOA Record

This displays the SOA (Start Of Authority) record for your domain. This is for information only.

SOA Serial Number

Checks the format of the serial number from the SOA. The serial number should denote the date of the last change in the format YYYYMMDDnn where nn is the number of changes on this day (starting at zero). (A serial number of 2007020300 would indicate that the last change was made on 3rd February 2007, and that was the only change made on that day). Some systems use the Unix timestamp for the serial number. The Unix timestamp is the number of seconds since 1st January 1970. (A Unix timestamp of 1170500702 would be 3rd February 2007 at 11:05:02 am).

The Serial Number is used to check that all of your name servers have the latest DNS settings for your domain. If your name servers have different serial numbers, this may indicate a replication problem between your servers and probably means that your servers are returning inconsistent data.

DNS Contact

Checks that the DNS contact listed in the SOA record is a real email address.

This should be the email address of the DNS administrator for your domain.

The DNS Contact email address is stored in the SOA record with the at (@) symbol replaced by a dot (.). The email address is shown here with the usual at (@) symbol for readability purposes.

DNS Master Name

This check verifies that the master (primary) name server listed in the SOA is a valid name server.

The master (primary) has the source records for your domain. All other name servers should replicate from this one. All DNS changes would be made on this name server.

Check Missing NS Records 1

Checks that all name server records (NS records) listed at the parent servers are also listed on the local name servers.

The NS records at the parent servers are not synchronised automatically with those at your name servers. So, if you make changes to the name server records at the parent servers, you must change them on your local name servers as well.

Check Missing NS Records 2

Checks that all name server records (NS records) listed on the local name servers are also listed at the parent servers.

The NS records at the parent servers are not synchronised automatically with those at your name servers. So, if you make changes to your local name server records, you must change them on the parent servers as well.

Glue Record Consistency

Checks that any glue records listed are consistent between the local name servers and the parent servers.

Glue records are helper records that need to be provided to help locate your name servers. You will need to provide glue records if your name servers are hosted on your domain name. The glue records are actually additional A records that resolve the name server to an IP address. The parent servers for your domain should return the glue records with your name server records.

Differences between the records returned by the parent servers and your name servers could cause inconsistent results.