samba - Feb 2008 - question about "Chapter 3. Secure Office Networking" DNS config

Hello:

Reviewing the config in "Samba-3 by Example" outlined here:

<http://us1.samba.org/samba/docs/man/Samba-Guide/secure.html#ch4dhcpdns> 

it's not apparent to me why 2 separate domains, samba.biz and
samba.us are being used.  Why not just one?  Or subdomain of samba.us
for internal w/different internal/external views, etc.?  I'm a unix
admin and pretty familiar with bind, but not a windows guy or very
familiar with DDNS, so if someone could shed some light on this it'd be
much appreciated:)

TIA--

-- 
Best regards,

Ken Gunderson

Q: Because it reverses the logical flow of conversation.
A: Why is putting a reply at the top of the message frowned upon?