JSI Tip 5617. DNS cannot create zones that contain reserved words.

When you are using non-Active Directory-integrated DNS, you cannot reload a zone that contains reserved words:

CON
AUX
COM1
COM2
COM3
COM4
LPT1
LPT2
LPT3
NUL
PRN

LPT2.org
NUL.com
PRN.co.uk

NOTE: If you create a zone with reserved words, it ceases to function when DNS is restarted.

To workaround this feature, use the DNSCMD utility to create the zone using a new name:

DNSCMD /ZONEADD nul.com /Primary /File nulinc.com.dns

NOTE: Zone files are named after the zone. Upper case is NOT permitted.