SOA record lookup
Read a zone's serial, refresh, retry, and expiry timers.
An SOA record lookup reads the Start of Authority record that holds a DNS zone's administrative settings. The tool reports the primary nameserver, the responsible contact, the serial number, and the refresh, retry, expire, and minimum TTL timers that govern how secondary servers stay in sync. Reading these values helps you confirm zone transfers are timed sensibly and that the serial increments with each change. Since a stuck serial or odd timer can quietly break replication, SJ Monitor can watch the SOA record and alert you when it changes.
Frequently asked questions
What is the SOA serial number for?
Secondary nameservers compare the serial to decide whether their copy of the zone is stale and needs a fresh transfer. It should increase every time you edit the zone.
What do the refresh and expire timers control?
Refresh sets how often secondaries check for updates, retry governs failed attempts, and expire defines how long a secondary keeps serving data if the primary is unreachable. Sensible values keep DNS resilient.
Can SJ Monitor watch my SOA record?
Yes. Continuous monitoring can track the SOA and alert you when the serial or any timer changes, catching replication problems early.
What serial number format should I use?
The common convention is YYYYMMDDnn (date plus a two-digit counter), which is easy to read and always increases. The only hard rule is that the serial must go up every time you edit the zone.
What is the minimum TTL field in the SOA?
Today it sets the negative-caching TTL — how long resolvers cache a "no such record" answer. A very high value means deletions and typos linger in caches longer than you might expect.
Why hasn't my secondary picked up changes?
Either the serial didn't increment so secondaries think nothing changed, or the refresh interval hasn't elapsed. Bumping the serial and confirming the refresh timer usually resolves stale secondaries.
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