Disjoint namespace is the term used if you have DNS names for windows active directory members which are anything other than:
samaccountname.<AD domain>
So, if you give your hosts DNS hostnames of:
samaccountname.dept.<AD domain>
...this is a disjoint namespace. This is a supported configuration in principle - AD itself and most of the Microsoft tools work just fine - but in practice you'll find an awful lot of 3rd party stuff out there assumes that the AD domain starts at the first "." in the hostname, and will break if it doesn't.
This makes me sad, since the underlying protocols at AD is built on (DNS, Kerberos, LDAP) have plenty of mechanisms for doing the mapping properly. They're just not used.
Okay. Fortunately, we're not doing that. "Missouri.edu" is not an AD domain. "Col.missouri.edu" however, is. So a dnps-caplap-4.col.missouri.edu is a computer named dnps-caplap-4 in the col.missouri.edu AD domain. So the "first dot" assumption should work IF you take "col.missouri.edu" as the domain, rather than just "COL" (that which is between the first two dots). --J