DNS区域文件（Zone file）的serial命名规则需要按照官方提供的文档命名，主要有2点需要注意。
1.命名时，Master DNS的Serial数值必须大于Slave DNS的，且全必须是数字；
2.Serial 数值不能是超过当前系统时间的未来的某个值，如现在是2013年10月29不能超过2013102900；
YYYYMMDDRR的格式如下：
The format for this line is YYYYMMDDRR where:
YYYY = The year (e.g. 2005)
MM = The month (e.g. 02)
DD = The day (e.g. 22)
RR = Today's revision of this file (e.g. 01)
Incrementing and Changing the Serial Number
Zone serial numbers are just numbers — they aren’t date related. A lot of people set them to a number
that represents a date, usually of the form YYYYMMDDRR. Occasionally they will make a mistake and
set them to a ”date in the future” then try to correct them by setting them to the ”current date”. This
causes problems because serial numbers are used to indicate that a zone has been updated. If the serial
number on the slave server is lower than the serial number on the master, the slave server will attempt
to update its copy of the zone.
Setting the serial number to a lower number on the master server than the slave server means that the
slave will not perform updates to its copy of the zone.
The solution to this is to add 2147483647 (2?31-1) to the number, reload the zone and make sure all slaves
have updated to the new zone serial number, then reset the number to what you want it to be, and reload
the zone again.
本文转自 urey_pp 51CTO博客，原文链接：http://blog.51cto.com/dgd2010/1394076，如需转载请自行联系原作者
