Why check DNS records
DNS turns a domain name into server addresses and stores service settings: where to deliver mail, who may issue SSL certificates, how to prove domain ownership. One wrong record and the site won’t load or emails land in spam.
Record types
- A / AAAA — the IPv4 and IPv6 address of the website’s server.
- CNAME — an alias pointing to another name.
- MX — the domain’s mail servers with priority.
- NS — the DNS servers that serve the zone.
- TXT — SPF, DKIM, DMARC and service verification codes.
- SOA — the zone’s primary server, serial number and refresh timers.
- CAA — the certificate authorities allowed to issue SSL for the domain.
- SRV — service locations, e.g.
_sip._tcp.example.com. - PTR — reverse record: the name assigned to an IP address.
Queries go through our server’s recursive DNS resolver, so after a zone change new values appear once the previous TTL expires. To simply find a domain’s IP, nslookup is more convenient.