The definition of SOA record
The SOA record, or Start of Authority, is one of the most important DNS records. It signifies the beginning of authority. It will direct you to the nameserver that holds the original zone file. This server will be the authoritative DNS server and have all of the critical information about the zone. The Start of Authority record is the first in a zone file, and it sets the zone’s general characteristics.
DNS servers are usually grouped together in a cluster. Each one of them must synchronize its zone file. They’ll need to undertake a zone transfer to accomplish this. The SOA record functions similarly to a controlling record. It contains a serial number and indicates which update is the most recent. Secondary servers, also known as secondary servers, monitor changes in the serial number. They then update and obtain the most up-to-date information from the authoritative server.
What is the purpose of the SOA record?
The SOA record has two main purposes, which are:
- to show the top authority about a zone. The goal of a DNS Start of Authority record is to show the top authority for a zone and its start date (the authoritative name server for the zone). Only one DNS Start of Authority record should exist for a zone, and SOA must be mandatory. Your zone will cease working if you try to add more than one DNS SOA record.
- to make a zone transfer. The DNS Start of Authority record is also used for zone transfer because it provides the most recent version of a zone’s DNS records and specifies whether or not the secondary DNS servers need to update.
The structure of the SOA record
The Start of Authority record includes the following element:
- Name – the name of the zone
- Type – SOA record
- Primary name server – The zone’s primary name server’s hostname.
- Admin’s email – The administrator of the domain’s zone file’s contact information.
- Serial number – The serial number of the zone. The secondary DNS servers will examine this value to determine whether or not to update the zone file.
- The refresh rate – number of seconds that the secondary name servers wait before checking for changes again.
- Retry rate – If the zone transfer between the secondary DNS servers and the primary DNS servers fails, this is the amount of time the secondary servers will try again.
- TTL – The default time-to-live for all DNS records in the zone file
How to check it?
- On Windows
Launch a command prompt. Then type:
nslookup -type=soa yourdomain.net
Then the information for the SOA record will appear. Replace yourdomain.net with the domain name you want to check.
- On Linux and macOS
Open the Linux Terminal and write the following command:
dig yourdomain.net SOA
We can conclude that it is crucial to understand your domain Start of Authority record and how it interacts with the connected DNS servers. SOA is one of the most fundamental and necessary records for the Domain Name System to function normally.