At 5:08 PM +0930 4/3/07, Tim wrote: >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. For zone files which are an ultimate answer and thus will never change, a convention is to use a serial number of "42". Don't change dead.zone now, though! The procedure for decrementing a zone serial number is, umm, convoluted. -- ____________________________________________________________________ TonyN.:' <mailto:tonynelson@xxxxxxxxxxxxxxxxx> ' <http://www.georgeanelson.com/>
