Upcoming change to SOA values in .com and .net zones

Matt Larson mlarson at verisign.com
Wed Jan 7 22:46:23 UTC 2004


VeriSign Naming and Directory Services will change the serial number
format and "minimum" value in the .com and .net zones' SOA records on
or shortly after 9 February 2004.

The current serial number format is YYYYMMDDNN.  (The zones are
generated twice per day, so NN is usually either 00 or 01.)  The new
format will be the UTC time at the moment of zone generation encoded
as the number of seconds since the UNIX epoch. (00:00:00 GMT, 1
January 1970.)  For example, a zone published on 9 February 2004 might
have serial number "1076370400".  The .com and .net zones will still
be generated twice per day, but this serial number format change is in
preparation for potentially more frequent updates to these zones.

This Perl invocation converts a new-format serial number into a
meaningful date:

$ perl -e 'print scalar localtime 1076370400'

At the same time, we will also change the "minimum" value in the .com
and .net SOA records from its current value of 86400 seconds (one day)
to 900 seconds (15 minutes).  This change brings this value in line
with the widely implemented negative caching semantics defined in
Section 4 of RFC 2308.

There should be no end-user impact resulting from these changes
(though it's conceivable that some people have processes that rely on
the semantics of the .com/.net serial number.)  But because these
zones are widely used and closely watched, we want to let the Internet
community know about the changes in advance.

Matt
--
Matt Larson <mlarson at verisign.com>
VeriSign Naming and Directory Services



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