Nameserver Problem [more] -

Tim ignored_mailbox at yahoo.com.au
Tue Apr 3 07:38:01 UTC 2007


Ed Greshko:
>>> While that works, you really should be updating the serial number each
>>> time you make a change to a zone file.  

Tim:
>> Yes, but there weren't any changes being made to that zone file.  So
>> it's not needed.  You'd only have to do that if you'd changed records
>> *in* it.  All we were doing is adding domains that used it.

Ed Greshko:
> I didn't mean to imply that something had changed.  Just making a statement 
> about the serial number and "good practice".

Only if the zone file had actually changed.  It's actually *bad*
practice to change a serial number on a zone if none of its details
changed.  It breaks caching, everything will reload it unnecessarily.

In this instance, it was leading Bob astray with an unrelated issue.
You don't change the serial number with each edit of your DNS server
configuration, just when it's actually necessary.

> While using a date format is only a recommendation it is considered by
> many to be good practice.

I've seen a few things which merely increment the serial number.  Such
as the DHCP that comes with Fedora.  If you started off using dates,
it'd just add one to the number, and you're left with a nonsense number
in the serial code.  Sure, it'll work, as it's a higher number, but it
won't mean what you think it did.

Using a date code is a simple way of putting in a new serial code
without caring what the prior number is.  But that has its own problems.
It can make a serial code go backwards if it was already a higher
number, because the last editor used a different scheme.  It's quite
easy for that to happen if you'd done numerous changes to a zone file in
one day, there's not enough digits in the code to do years+months+days
+hours+minutes+extra_changes.  At least, not enough digits in some DNS
servers that I've used.

  From a programatic point of view, you really need to check what the
number was, and *at* *least* increment it by one.  But *only* do so when
needed.

-- 
(This box runs FC6, my others run FC4 & FC5, in case that's
 important to the thread.)

Don't send private replies to my address, the mailbox is ignored.
I read messages from the public lists.





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