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TR7Enterprise Application Delivery & Security Platform
What is an SOA record; what do its fields mean?
Short answer
The SOA (Start of Authority) record is the single record per zone that carries the authority information of a zone (RFC 1035). Its fields: the primary name server (MNAME), the e-mail address of the administrator (RNAME; a dot is written instead of @), serial, the check interval of the slave servers (refresh), the retry time after a failed check (retry), the validity limit of data that cannot be updated (expire) and the minimum field (today the cache duration of negative answers, RFC 2308). Slave servers transfer the zone again when the serial increases. TR7 GTM automatically creates the SOA record in every domain with the content ns1.@ hostmaster.@ 10800 3600 1209600 3600 (@ is replaced with the domain name); the fields are edited on the Records screen, while the serial advances automatically on changes according to the SOA Format selection of the domain (default YYYYMMDD01 format).
Where It Is Used in TR7
| Where | Field / label | What for |
|---|---|---|
| GTM → GTM Services → service name → Records → SOA record → Edit | SOA MNAME, SOA RNAME, SOA Refresh Rate (s), SOA Retry Rate (s), SOA Expire Time (s), Soa Default TTL (record type specific fields) | The values of the SOA fields; the serial field is not in the form |
| GTM → GTM Services → service name → Domains → Add / Edit | SOA Format (YYYYMMDD01 format, Increase by 1, Current UNIXTIME) | How the serial advances on changes |
| Domains → domain preview | Current SOA Record (preview) | The SOA content the device is serving at that moment; separate for each device in a cluster |
Fields
| SOA field | Meaning | TR7 label | TR7 default | Range |
|---|---|---|---|---|
| MNAME | Primary name server | SOA MNAME | ns1.<domain>. | Name ending with a dot |
| RNAME | Administrator e-mail | SOA RNAME | hostmaster.<domain>. | Name ending with a dot |
| Serial | Zone version | - | According to SOA format | Managed automatically |
| Refresh | Check interval of the slave | SOA Refresh Rate (s) | 10800 | 0–43,200 |
| Retry | Retry after a failed check | SOA Retry Rate (s) | 3600 | 0–2,419,200 |
| Expire | Validity limit of the data if it cannot be updated | SOA Expire Time (s) | 1209600 | 0–2,419,200 |
| Minimum | Cache duration of negative answers (NXDOMAIN, NODATA) | Soa Default TTL | 3600 | 0–2,419,200 |
- The SOA record is always in the first row of the Records list; its Balance Algorithm is always First Healthy Record and a single SOA row is served in the answer.
- If the domain's local data center group is fed by Express, the SOA, including the serial, is served as it comes from the master server and the SOA format is not applied for this domain.
Common Misconceptions
- "If the SOA record is deleted, the zone is left without an SOA." TR7 recreates the deleted SOA record with the default content; no second SOA record is added.
- "The serial must be increased manually on every change." TR7 advances the serial automatically according to the SOA format selection; there is no serial field in the form.
- "Soa default TTL is the TTL of all records." The TTL of each record comes from its own TTL field; this field of the SOA determines the cache duration of negative answers.
How it is done in the documentation
