Reference: How SOA serial numbers are calculated - BlueCat Address Manager - 9.2.0

Address Manager Administration Guide

prodname
BlueCat Address Manager
version_custom
9.2.0

When you select AUTO:

  • For new zones or when DNS isn't already running on a managed server, there is an attempt to set the serial number based on the last known serial number of the zone. If the attempt fails, a new SOA serial number is calculated using an equation based on the system time (the current system time in seconds since midnight on January 1, 2001).
  • For existing zones that have been previously deployed, the server checks for changes made to the zone and increments the existing serial number by the number of changes. If this increment exceeds 2,147,483,647, the serial number is reset and is calculated using the system time calculation (the current system time in seconds since midnight on January 1, 2001).

When you select DATE:

  • For new zones or when DNS isn't already running on a managed server, a new SOA serial number is created by appending “00” (two zeroes) to the current system date. The current system date is in the format YYYYMMDD. For example, a date-based serial number set on February 21, 2014, would display as 2014022100.
  • For existing zones that have been previously deployed, the server checks for changes made to the SOA record:
    • If changes are present, the last two digits of the date-based serial number are incremented by 1. For example, the serial number 2014022100 would be incremented to 2014022101.
    • If the last two digits are “99”, the date part of the serial number is incremented by 1 and the last two digits are reset to “00” (two zeroes). For example, the serial number 2014022199 would be incremented to 2014022200.
    • If the serial number exceeds 2,147,483,647, it's reset by appending “00” (two zeroes) to the current system date.

When you select MANUAL:

  • You can specify an integer in the range of 0 to 4,294,967,295.
  • Changes to the zone will increment the manually-set number by 1.
    Note: If the manually-set number is smaller than the existing serial number, the manually-set number isn't deployed.