Free DNS tool
DNS SOA Record Lookup
Read the start-of-authority record for any domain: its primary name server, contact, serial number and zone timers.
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Lookups run in your browser over Google public DNS-over-HTTPS (Cloudflare as fallback). Nothing you enter is sent to Pulsetic.
DNS decides where your domain and email actually go. Pulsetic watches your domain and SSL certificate around the clock.
What is an SOA record?
Every DNS zone has exactly one SOA (start of authority) record. It names the primary name server and the zone administrator email, and it holds the serial number and the timers that control how secondary servers stay in sync with the primary.
The administrator email is written with a dot instead of the first at sign, so hostmaster.example.com means hostmaster@example.com. The fields after it are the serial, refresh, retry, expire and minimum-TTL values.
How to read SOA results
The serial number is the one to watch. It should increase every time the zone changes, and secondary servers use it to decide whether to pull an update. If you changed a record but the serial did not move, the change may not propagate to secondaries.
The refresh, retry and expire timers govern how long secondaries wait between syncs and how long they keep serving if the primary is unreachable. The final value is the negative-cache TTL, how long a "no such record" answer is remembered.
Look it up from the terminal
Prefer the command line? These return the same records this tool shows:
dig example.com SOA +short
nslookup -type=SOA example.com
Every DNS record type
What each record does. Each one has a dedicated lookup in the tabs above.
| Record | What it does | Example value |
|---|---|---|
| A | Maps a domain to an IPv4 address. | example.com → 93.184.216.34 |
| AAAA | Maps a domain to an IPv6 address. | example.com → 2606:2800:220:1:: |
| CNAME | Points one name at another name, as an alias. | www → example.com |
| MX | Names the mail servers that accept email for the domain, each with a priority. | 10 mail.example.com |
| TXT | Holds free-form text, used for SPF, DKIM, DMARC and domain verification. | v=spf1 include:_spf.google.com ~all |
| NS | Lists the authoritative name servers for the domain. | ns1.example.com |
| SOA | Start of authority: the primary name server and the zone refresh, retry and expiry timers. | ns1.example.com . 2026010101 |
| PTR | Reverse record: maps an IP address back to a host name. | 34.216.184.93.in-addr.arpa |
| SRV | Locates the host and port for a specific service. | _sip._tcp → 5060 sip.example.com |
| CAA | States which certificate authorities may issue SSL certificates for the domain. | 0 issue "letsencrypt.org" |
Frequently asked questions
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What is an SOA record?
The SOA, or start of authority, record sits at the top of every DNS zone. It identifies the primary name server and the zone admin contact, and carries the serial number and timing values that keep secondary servers in sync.
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What is the SOA serial number for?
It is a version stamp for the zone. Each change should raise the serial, and secondary name servers compare it against their own copy to decide whether to pull an update. A serial that never changes can leave secondaries serving stale data.
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Why is the admin email written with a dot?
DNS uses the first label as the local part, so the at sign is replaced by a dot. hostmaster.example.com in an SOA record means hostmaster@example.com.
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What are the SOA refresh, retry and expire values?
They are seconds. Refresh is how often a secondary checks the primary, retry is how long it waits after a failed check, and expire is how long it keeps answering before giving up if the primary stays unreachable.
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