DNS on Windows Server 2003, 3rd Edition

1. Forget to Increment Serial Number

This particular problem occurs only if you make changes to your zone datafile by hand, without using the DNS console. The DNS console remembers to increment the serial number in the SOA record each time it changes zone data, so you don’t have to worry about it. However, this also means that you probably won’t be in the habit of updating the serial number, so you may forget when making that one-off manual modification.

The main symptom of this problem is that secondary name servers don’t pick up any changes you make to the zone on the primary server. The secondaries think the zone data hasn’t changed since the serial number is still the same.

How do you check if you remembered to increment the serial number? Unfortunately, that’s not so easy. If you don’t remember what the old serial number was and your serial number gives you no indication of when it was updated, there’s no direct way to tell whether it has changed.^[1] When you start the primary, it loads the updated zone datafile regardless of whether you’ve changed the serial number. About the best you can do is to use nslookup to compare the data returned by the primary and by a secondary. If they return different data, you probably forgot to increment the serial number. If you can remember a recent change you made, you can look for that data. If you can’t remember a recent change, you can try transferring the zone from a primary and from a secondary, sorting the results, and using a file-comparison ...