SOA record: What is it and how to use it?

Today we will explore one of the most fundamental DNS record types, which exactly is the SOA record. First, we will see what is its definition and then we will take a look at its structure. Finally, we will explain why is SOA record so critical for properly working the Domain Name System.

SOA record – Meaning

The most essential component of a Zone file is an SOA (Start of Authority) record. The SOA record is a mechanism for the domain administrator to provide basic details about the domain, such as how frequently it is updated, when it was last updated when to check back for more information, what the administrator’s email address is, and so forth. It establishes the general attributes of the zone and is the first DNS record in a zone file. Only one SOA record may be present in a Zone file.

What does it look like?

This is what you will see when you open a Start of Authority record:

  • Name: Name set by the DNS administrator.
  • Type: The DNS record’s type, which is SOA.
  • Primary name server: The authoritative DNS server for that zone
  • Admin’s email: Email address of the administrator for the zone’s DNS records.
  • Serial number: The zone’s previously specified serial number. It will state whether or not the backup DNS servers need to modify their DNS records.
  • Retry rate: If the zone transfer attempt from the primary DNS server fails, this number defines how long the secondary DNS server should try again.
  • Refresh rate: This value indicates how frequently the secondary DNS server must check for updates on the authoritative DNS server.
  • Default TTL: This value indicates the length of time that DNS records remain valid. The secondary DNS servers must delete them when the allotted time has passed and restart zone transfer.

Why is the SOA record critical?

A properly configured and maintained Start of Authority record can boost website access speed, decrease nameserver bandwidth usage, and keep a website online even if the primary DNS server is unavailable.

In addition, you need an SOA record to perform zone transfers and to identify the authoritative name server. There should only be one SOA record per zone, and each zone must have one. Your zone won’t work if it has no SOA records or numerous SOA records per zone. 

Conclusion

Let’s review. SOA records hold administrative data such as the domain or zone name, serial numbers, and refresh information. Without it, the DNS zone won’t work. So, it is critical to implement it in your Domain Name System if you want it to work correctly.

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