The last record you need to know is the SOA record, which is a mandatory record in all zone files, and is used to describe the zone and configure how often nameservers should update the zone file for this domain. It also has a version counter that ensures that only the latest version of the zone file is propagated:
hobnob.social. IN SOA ns1.digitalocean.com. dan.danyll.com ( <serial>, <refresh>, <retry>, <expiry>, <negativeTTL> )
The first few values are similar to the ones in the NS records. The rest are as follows:
- ns1.digitalocean.com is the primary master nameserver, which holds the most up-to-date zone file. There may be slave nameservers that mirror the primary nameserver to reduce its load.
- dan.danyll.com ...
