Problems with a serial number > 3000000000?

[Martin Jericho]

I have a problem with an alias I set up, and after hours of reading RFCs I'm
still no closer to a solution.
The domain is called "infoserv-consulting.com", in which two server names
are defined, "www" and "xap".
Both names work perfectly for me using different name servers in Germany,
but a friend of mine in Australia said he gets the following message when
trying to access "xap", although "www" works ok:

ERROR
The requested URL could not be retrieved
While trying to retrieve the URL: http://xap.infoserv-consulting.com/
The following error was encountered:
     DNS name lookup failure
The system returned:
    DNS Domain 'xap.infoserv-consulting.com' is invalid: Host not found
(authoritative).
This means that:
    The specified host does not exist or its address can't be found.
Generated by squid/1.1.22 at gateway

I suspect the problem lies in the fact that I had to set the serial number
to over 3000000000 after adding the "xap" alias, because someone had
inadvertantly made the serial number an eleven digit number at some stage,
which many name servers took to be 2800000000 or something after conversion
to an unsigned 32bit integer.  I changed it back to a ten digit number but
because the number was then smaller than what the other servers had, they
wouldn't update their caches anymore.  That's the story why the serial
number is over 3000000000.

Here is the "infoserv-consuilting.com.file":

@ IN SOA infoserv06.infoserv-consulting.de. root.infoserv-consulting.de.
( 3000060601 10800 3600 3600000 86400 )
                NS      infoserv06.infoserv-consulting.de.
                NS      pns.dtag.de.
                NS      techfac.techfak.uni-bielefeld.de.
                MX 5    infoserv9.infoserv-consulting.de.
localhost       A       127.0.0.1
infoserv9       A       212.184.24.98
www             CNAME   infoserv9.infoserv-consulting.de.
xap             CNAME   infoserv9.infoserv-consulting.de.

The "xap" alias has been there for a couple of weeks, so I think it should
have reached even Australia by now!
Does anyone have any idea whether the problem is related to the serial
number, and what I can do about it?
I found the following information in RFC1034:

"Serial number advances
and comparisons use sequence space arithmetic, so there is a theoretic
limit on how fast a zone can be updated, basically that old copies must
die out before the serial number covers half of its 32 bit range.  In
practice, the only concern is that the compare operation deals properly
with comparisons around the boundary between the most positive and most
negative 32 bit numbers."

I've got to admit I don't know what "sequence space arithmetic" is, or
whether this could also be related to the problem.

Is there any way I can set the serial number back to its normal value?

Thanks very much for any assistance!
Martin