SOA Parameters

The soa node is presented by type SOAType (plesk_dns.xsd). This type has the following graphics representation:

• The ttl node is optional. This is the amount of time (in seconds) that slave DNS servers should store the record in a cache. Plesk sets the default value of one day. Data type: unsignedInt.
• The refresh node is optional. This is how often (in seconds) the slave name servers check with the primary name server to see if any changes have been made to the site zone file. Plesk sets the default value of three hours. RFC 1912 recommends to vary this parameter from 1200 to 43200. Use the 1200 value if your data is volatile and 43200 if not. Data type: unsignedInt.
• The retry node is optional. This is the time (in seconds) a slave (secondary) DNS server waits before retrying a failed zone transfer. This time is typically less than the refresh interval. Typical values vary from 180 (three minutes) to 900(15 minutes). Plesk sets the default value of one hour. Data type: unsignedInt.
• The expire node is optional. Signed 32-bit value in seconds. Indicates when the zone data is no longer authoritative. Applies to Slaves or Secondary servers only. BIND9 slaves stop responding to queries for the zone when this time has expired and no contact has been made with the master. Thus when the ref values expires the slave will attempt to read the SOA record for the zone - and request a zone transfer AXFR/ IXFR if the sn has changed. If contact is made the expiry and refresh values are reset and the cycle starts again. If the slave fails to contact the master, it will retry every retry period but continue to supply authoritative data for the zone until the expiry value is reached, at which point it will stop answering queries for the site. RFC 1912 recommends 1209600 to 2419200 seconds (2-4 weeks) to allow for major outages of the master. Plesk sets the default value of one week. Data type: unsignedInt.
• The minimum node is optional. This is the time (in seconds) during which a secondary server should cache a negative response. The maximum value allowed by BIND 9 for this parameter is 3 hours (10800 seconds). Plesk sets the default value of three hours. Data type: unsignedInt.